
Ask HN: How do I learn C properly? - buchanae
I have 15+ years of experience in many languages: javascript, python, go, etc.<p>I can write C, but I&#x27;m not confident I&#x27;m doing it the right way. There are now decades of forums and blogs I can search through, but I&#x27;d love to have a single, clean, clear source of truth for recommendations on how to write C code.<p>I&#x27;ve started reading &quot;Modern C&quot; by Jens Gustedt. I&#x27;m not sure if this is the closest to a modern source of truth.<p>Note, I&#x27;d like my C code to work on Windows, which possibly restricts the &quot;right way&quot; to features provided by C89. But again, I&#x27;m not sure, the internet is super clear on this.<p>Thanks for the tips!
======
sramsay
It sounds like you're not asking, "How do I learn the language?" but "How do I
know I'm doing it right?"

I think Gustedt's book is superb if you're just trying to learn the language,
and it does a good job of presenting the most up-to-date standard. I admire
the K&R as much as anyone else, but it's not exactly an up-to-date language
resource at this point, and it doesn't really provide any guidance on the
design and structure of systems in C (that's not it's purpose).

You might have a look at Hanson's _C Interfaces and Implementations:
Techniques for Creating Reusable Software_. That's focused on large projects
and APIs, but it will give you a good sense of the "cognitive style" of C.

 _21st Century C_ is very opinionated, and it spends a great deal of time
talking about tooling, but overall, it's a pretty good orientation to the C
ecosystem and more modern idioms and libraries.

I might also put in a plug for Reese's _Understanding and Using C Pointers_.
That sounds a bit narrow, but it's really a book about how you handle -- and
think about -- memory in C, and it can be very eye-opening (even for people
with a lot of experience with the language).

C forces you to think about things that you seldom have to consider with
Javascript, Python, or Go. And yes: it's an "unsafe" language that can set
your hair on fire. But there are advantages to it as well. It's screaming-
fast, the library ecosystem is absolutely gigantic, there are decades of
others' wisdom and experience upon which to draw, it shows no signs of going
away any time soon, and you'll have very little trouble keeping up with
changes in the language.

It's also a language that you can actually hold in your head at one time,
because there's very little sugar going on. It's certainly possible to write
extremely obfuscated code, but in practice, I find that I'm only rarely
baffled reading someone else's C code. If I am, it's usually because I don't
understand the problem domain, not the language.

~~~
nicoburns
Do any of these resources help with learning how to deal with:

1\. The lack of abstractiom in C? 2\. All of the pitfalls and gotchas:
Undefined Behaviour, use after free, etc?

I've been writing Rust for a couple of years now, so I'm quite comfortable
with low-level ideas, memory management, etc. But C still scares me because it
seems so easy to make mistakes, and I also often find it hard to see the
forest for the trees.

Perhaps C's just not for me?

~~~
throwaway17_17
I think both “Expert C” and “Modern C” do a reasonably good job working
through memory management patterns, strategy, and constructs. However, I’m
using this comment as an attempt discuss another topic you raised in your
comment.

I don’t mean for this to be flame bait, but I do think it is worth pointing
out and discussing if you desire. The concept of memory management that is
presented in a majority of the Rust that I have seen written outside of deep
library code and the parts of the low-level implementations of some standard
library functions has very little relation to the analogous concepts in C. I’d
say that what Rust considers memory management in average code is more similar
to programming in C without using any heap allocation. I could be wrong or
could just have not seen the right code bases, but there is very little C
style byte level ‘data structure’ layout design and then the allocation of
those sorts of data using multiple allocation strategies.

I certainly understand that the above mentioned constructs and patterns are
really not part of Rust’s idiomatic usage, and that a chunk of C’s allocation
options are semi-prohibited because of Rust’s memory model. But, if you are
coming from Rust and going into C, the differences are far greater than the
similarities in this area.

I’m certainly not questioning your credentials, experience, or ability, I
really just feel like this area is lacking any substantial discussion where
said discussion is not focused on the merits/drawbacks of the language design.
You clearly know Rust and seem to be open to learning or working with C, so it
isn’t about Rust v. C, it’s about compare and contrast, and highlighting the
fundamental differences that could cause some mental roadblocks.

P.S. Sorry for rambling, Day Light Savings time is kicking my ass.

~~~
jolux
Not parent but Rust definitely makes you think about a lot of important
aspects of memory management like lifetimes and references and ownership and
stuff. In fact, it makes it impossible not to think about them: they're
enforced by the compiler.

Those mechanics are pretty important but Rust definitely lets you program with
values on the heap as well, it just does it in a strongly-typed fashion. I
will agree that smart pointers are generally easier to work with, particularly
with things like deref coercion, but Rust is philosophically closest to a
language like C++ but with a stronger type system, memory safety, and lots of
footguns removed.

I think Rust gives someone a better basis for learning and writing C than
probably any other modern language.

~~~
TurboHaskal
I grokked C only after dabbling with Forth. C is too high level to know what's
going on at the hardware level.

~~~
jolux
Most processors these days are basically running C virtual machines in
hardware anyways.

------
krychu
The proper way to learn C is to get a good book, read it, and do exercises
along the way.

Here’s an excellent book: C Programming: A Modern Approach, by King.

Avoid online tutorials, and know that there are many poor books on C,
including the recommended here “Learn C the Hard Way”. It has factual
problems; see under “Stuff that should be avoided” here:
[http://iso-9899.info/wiki/Main_Page](http://iso-9899.info/wiki/Main_Page)

Note also, that unlike some other languages, C is not a language that you
should learn by “trying things out”, due to the nature of “undefined
behavior”.

Another recommendation would be to ask for CR on IRC.

Good luck!

~~~
JustSomeNobody
> Note also, that unlike some other languages, C is not a language that you
> should learn by “trying things out”, due to the nature of “undefined
> behavior”.

I disagree. You have to learn the ways in which things fail in any language
you learn, especially a language like C.

~~~
clarry
The point is that you don't learn all the ways in which things fail in C by
trying. At best, you learn the way in which they fail (or fail to fail!) on
your specific platform/compiler/version/compiler options combo.

If you want to know how things can fail (or, what things can fail in
unspecified ways), you have to do a bit of reading and no amount of trying and
experimenting will conjure that knowledge.

~~~
zzzcpan
There isn't a guide to learn how things fail on platform, compiler, version,
options combo. Probably the only things that force you to systematically
research and accumulate such knowledge is by writing a language VM in C or use
C as an intermediate representation. Even writing a C compiler itself won't
teach you that.

~~~
clarry
> There isn't a guide to learn how things fail on platform, compiler, version,
> options combo.

Yeah, that's the point. Chasing that knowledge is pointless. Instead, read the
spec and find out what is legal and what is not. What is defined and what is
not. Then you can stop worrying about how things fail and start worrying about
not doing those things.

~~~
ianai
Trying c out with a known solid testing framework seems like a much more
practical and useful way to start. Telling people to read a text wall before
doing any practice at any task is a great setup for failure. Math doesn’t do
that. Physics doesn’t do that. Chemistry doesn’t do that. Literature doesn’t
do that. Philosophy doesn’t do that. Etc. and of those philosophy is almost
the study of text walls. But the best philosophy courses tend to start with a
Socratic dialogue which is basically live action philosophizing.

~~~
kqr
Well, we also have lots of historic evidence (nearly every application written
in C ever) that traditional/intuitive teaching methods _don 't work for C_.

All people have learned from the last 40 years of C is how to write
ridiculously insecure applications.

Reading the standard may not be the optimal choice, or even the first choice,
but common teaching methods are nearly guaranteed to produce crap results _in
the specific case of C programming_.

~~~
MaxBarraclough
I broadly agree. More so than any other other language, you cannot produce a
good C (or C++) programmer by try-it-and-see alone. It's vital to have a grasp
of the way the language is defined.

Point of disagreement: no amount of C expertise makes a hand-written C
codebase safe. Vulnerabilities and undefined behaviour are often found even in
code written by top-flight C programmers.

------
ndesaulniers
I work on Clang and the Linux kernel. JavaScript was the first language I feel
I've mastered, before C. Of the many C books I have and have read, I only
recommend 2:

Head First C by Griffiths and Griffiths

Expert C Programming: Deep C Secrets by van der Linden

The first is an excellent introduction, especially if you treat it as a
workbook.

The second is a great intermediate book.

Really advanced stuff comes from seeing things in the wild.

~~~
ndesaulniers
Also, Jens' book is great, and I've learned from reading it, but it is way too
long for a beginner.

------
grafelic
An interesting way IME to learn C, is to code for an old platform like the
Amiga.

All the same best practices apply, but the underlying OS is more simple and
the constraints, like missing floating point, forces you investigate many
aspects of C.

You can use Bebbo's m68k cross compiler to compile for the platform:
[https://github.com/bebbo/amiga-gcc](https://github.com/bebbo/amiga-gcc)

No single source of truth for C best practices exist, but I can recommend
using static analyzers like:

[https://splint.org/](https://splint.org/)

and

[http://cppcheck.sourceforge.net/](http://cppcheck.sourceforge.net/)

to steer you in the right direction.

Also, compile your code with the following gcc options: -pedantic -std=<c99 or
c89> -ggdb3 -O0 -Wall -Wextra -Wformat=2 -Wmissing-include-dirs -Winit-self
-Wswitch-default -Wswitch-enum -Wunused-parameter -Wfloat-equal -Wundef
-Wshadow -Wlarger-than-1000 -Wunsafe-loop-optimizations -Wbad-function-cast
-Wcast-qual -Wcast-align -Wconversion -Wlogical-op -Waggregate-return
-Wstrict-prototypes -Wold-style-definition -Wmissing-prototypes -Wmissing-
declarations -Wpacked -Wpadded -Wredundant-decls -Wnested-externs
-Wunreachable-code -Winline -Winvalid-pch -Wvolatile-register-var -Wstrict-
aliasing=2 -Wstrict-overflow=2 -Wtraditional-conversion -Wwrite-strings

Not that they all necessarily always makes sense, but they will reveal weak
points in your code.

------
lmilcin
Given the fact you already know some higher level languages I think the best
way to learn C is to go low level.

C is fantastic language because it is within your reach to go and understand
all small details of how various features are actually implemented. I find it
very helpful to be able to understand how a piece of code actually functions
on a low level.

Another tip: you are used to having high level features on your disposal.
Don't try to duplicate those features. Figure out how actual C projects deal
with program structure and flow issues that you are used to solving with high
level constructs.

~~~
__s
CPython is a particularly nice codebase to dig into. Plus, there's a big todo
list: [https://bugs.python.org](https://bugs.python.org)

------
pritovido
C is a very simple language. I have used just the official old book to create
a compiler for it:

[https://www.amazon.com/Programming-Language-2nd-Brian-
Kernig...](https://www.amazon.com/Programming-Language-2nd-Brian-
Kernighan/dp/0131103628)

The best thing you can do is finding some open source code that interest you,
read it and write it.

For example, I write my own controllers for CNCs, and there are lots of code
for controlling stepper motors out there. I also learned OpenGL and sockets
this way long time ago.

On the other hand, C is a terrible language for any big project unless you
automate it some way.

I use mostly lisp in order to write C code automatically. C is too low level
for writing any substantial code. Lisp has things like Macros(nothing to do
with c macros) that can make you write code 10x, to 50x faster easily.

~~~
3fe9a03ccd14ca5
> _The best thing you can do is finding some open source code that interest
> you, read it and write it._

Has reading source code in a language that’s unfamiliar to you shown to be of
any real benefit to learning? It seems you need at least a little bit of
foundational experience with it before your brain can even parse what you’re
seeing in a beneficial way.

~~~
dandigangi
I'd tend to agree here also. I didn't start reading source code until a couple
years in because I couldn't really put it to use. It becomes 10x more valuable
when I was deep into my career learning from the big shots.

It _can_ help no doubt but not sure that's the best way to start. Especially
with a language like C. It's not so straight forward without some training or
CS education.

~~~
clarry
> It becomes 10x more valuable when I was deep into my career learning from
> the big shots.

Yeah well OP said they've 15+ years of experience so..

> Especially with a language like C. It's not so straight forward without some
> training or CS education.

I agree with pritovido, when they say C is a very simple language. Sure, it
has grown its quirks and gotchas along with some cruft (the kind of things you
wouldn't learn about in a CS curriculum anyway), but at its core it really is
very simple.

------
jakobdabo
In addition to the other recommendations, make sure you fully understand the
memory model of your target architecture, the stack, the heap, the linkage.

Also, understand the undefined behavior, the compiler optimizations and how it
can affect your code if you forget about the UB or if you ignore the compiler
warnings, and read about the `volatile` keyword.

And a personal tip, please tell the compiler not to use strict aliasing (I
think it's stupid) - you will get rid of some UB without much sacrifice.

~~~
krychu
Just to be clear, heap and stack are not part of C.

~~~
Canada
Then why does it make a difference whether you dereference a pointer to the
stack or the heap at any point in your program?

The hardware representation of an int isn't part of C either but it most
certainly had an effect on how your program will run.

~~~
clarry
> Then why does it make a difference whether you dereference a pointer to the
> stack or the heap at any point in your program?

Ok, I'll bite. What difference does it make?

~~~
smcameron
Because stack pointers are short lived, while heap pointers can be longer
lived.

Say you have a queue of pointers that some thread is chewing on, you can't
stick a pointer to a stack variable into that queue and then exit the scope of
that stack variable, but you could put a longer lived heap pointer into that
queue and exit the scope of the pointer, essentially passing ownership of the
pointer to whatever's chewing on the other end of the queue.

~~~
saagarjha
The C standard does not talk about a heap or the stack; you could implement a
"heap" by handing out pointers from the top level stack frame if you wanted
to.

~~~
camgunz
Is this important? By far the common case in C is using heap allocation as
implemented by your libc or crt. It's pretty essential knowledge.

------
quelsolaar
Once you know the basics watch this:
[https://www.youtube.com/watch?v=443UNeGrFoM](https://www.youtube.com/watch?v=443UNeGrFoM)

;-)

------
tmotwu
Like anything else, set yourself a goal for a project. What kinds? C today is
typically used for developing embedded systems, kernel internals, or device
drivers.

Depending on how deep you want to go. The most in depth way to understand C is
to learn assembly on an ISA first.

------
pyuser583
If you’re an experienced programmer, with some understanding of C, I
recommend: “Expert C Programming: Deep Secrets” by Peter van der Linden.

It’s one of the best books in the world. About anything. Ever.

~~~
jjgreen
I was going to post the same, now I don't have to, fabulous book.

------
jussij
> Note, I'd like my C code to work on Windows, which possibly restricts the
> "right way" to features provided by C89

That might be the case if you plan to use the Microsoft C compiler as they
have publicly said the don't have plans to update their C compiler.

However that is not your only option, since clang and several GCC ports will
also work on Windows.

~~~
giancarlostoro
Are you not able to use their C++ compiler to get modern features? My
understanding is that C++ is a superset and that a C++ compiler is also
usually a C compiler. Is this view incorrect for modern implementations?

~~~
jki275
C++ is not a strict superset of C anymore. You can't compile all C in a C++
compiler.

~~~
leetcrew
has c++ ever been a strict superset of c?

afaik,

    
    
      int* arr = malloc(sizeof(int));
    

has never worked in c++.

~~~
jki275
It's probably never been a strict superset really.

------
juped
This is actually pretty hard. I recommend reading C codebases, but it can be
hard to know which ones are good. Code to C99 for now; keep an eye on C11 etc.
Have a personal library of C implementations of things. Don't worry about
being on Windows, although if you're doing Windows development C#/.NET is the
lowest friction path.

I'm writing a book on C. I don't think it will ever be finished or see
publication. I recommend writing a book yourself - it's a great way to learn,
and maybe you're a better writer than me and will publish it.

------
begriffs
It's hard to beat this list of quality books:

[http://iso-9899.info/wiki/Books#Learning_C](http://iso-9899.info/wiki/Books#Learning_C)

Read some and do the exercises. You'll learn to write portable code to a
standard rather than stuff that "accidentally works." There's a lot of crap C
code in the world, full of GNUisms, overzealous macros, header-only nonsense
abusing translation units, and copypasta. Don't pick up bad habits from that
stuff.

------
carapace
Learn (a little bit of) assembly first. It will make more sense IMO if you
came at it from below rather than above, so to speak.

------
Areading314
I would recommend "Learn C the Hard Way" by Zed Shaw to get you started for
something practical, because it goes over how C is written in the real world.
Of course, situations will vary. The original book about C by K&R is an
excellent book too.

~~~
Paperweight
Zed makes it clear in that book that he hates C and doesn't use it anymore due
to its undefined behaviour.

~~~
saagarjha
Zed isn't actually very good at understanding undefined behavior and has
demonstrated this loudly and repeatedly. I would steer clear of his book,
personally.

------
keithnz
There is no clear source of truth for C. Depending on what you want to do
there is quite different approaches. C for embedded systems tends to look
quite different from C for systems programming. For instance MISRA is a C
coding standard for embedded devices in Motor Vehicles (but many of its ideas
are ideas from writing robust embedded systems), it says don't use things like
dynamic memory. You'd never use that if you are writing software for
linux/windows. So learning C "properly" would be about learning the different
approaches people use in C to write robust code and what tradeoffs they are
making. Understanding the C standard and the variations. Understanding bare
metal programming. Understanding the effect of different underlying processors
and hardware architectures. Understanding systems programming and how to
consume APIs and how to create reusable binary modules. Understanding the
compiler/build system the intermediate files / code generation / memory
layout. Read a variety of books ( including K&R ) and study code ( Luas
implementation is some very nicely written C )

------
chucksmash
I liked "C Programming: A Modern Approach"[1]. It has been several years but
as I recall it was well suited for self study and was pretty explicit in
calling out places it was talking about C99 as opposed to C89.

[1]: [https://www.amazon.com/C-Programming-Modern-
Approach-2nd/dp/...](https://www.amazon.com/C-Programming-Modern-
Approach-2nd/dp/0393979504)

~~~
chucksmash
You might also take a look at this Minecraft clone in C[1]. Uses sqlite to
persist state so you can see how you might interact with a database as well.
Quite modern and readable in that most functions outside main.c are <20 lines
long. It's also cross platform and should work on Windows, Mac and Linux.

[1]: [https://github.com/fogleman/Craft](https://github.com/fogleman/Craft)

------
fhars
Essential reading:

[https://blog.regehr.org/archives/213](https://blog.regehr.org/archives/213)

[http://blog.llvm.org/2011/05/what-every-c-programmer-
should-...](http://blog.llvm.org/2011/05/what-every-c-programmer-should-
know.html?m=1)

~~~
jstimpfle
omg no. Stop obsessing about this dragon. I'm not sure I've ever met it in my
life (you know, other than segfaults from NULL dereferences which are UB too).

~~~
saagarjha
How much C have you written, and how much has gone through a high-performance
optimizing compiler?

~~~
jstimpfle
I don't know. Quite a bit - maybe written 300K lines and deleted > 200K lines.
Most of it was compiled by gcc -O2 and/or MSVC. I've never relied on
vectorization or used a lot of intrinsics, though.

~~~
saagarjha
I'm honestly quite surprised you've _never_ run into surprising behavior
caused by the optimizer handling undefined behavior…

~~~
jstimpfle
Not that I'm aware of it.

------
flohofwoe
The Visual Studio C compiler (not the C++ compiler) supports "almost all" of
C99, I would definitely recommend skipping C89, and use at least the new
initialization features from C99 because they can reduce bugs caused by
uninitialized data. Also, C++ compilers support a subset C99 that's somewhere
around "C95" and is already a much friendlier version compared to C89.

TBH, I think the best way to learn C is to tinker a bit with assembly first
(it doesn't have to be a modern assembly dialect, just write a few 6502 or Z80
assembly programs in a home computer emulator). Coming from "below" instead of
"above" C's abstraction level helps understanding the design rationale behind
C, and the trade-offs between flexibility and unsafe memory handling.

------
dandigangi
I learned a few basic levels of C using my subscription to pluralsight.com.

But... I quickly switched to Rust as I see it being the C of the future as it
continues to develop. That's just me though. (I have similar opinions towards
things like Kotlin or Go.)

The books I am reading in the comments below are great resources.

------
cryptonector
With C++, going modern-first is a great approach. But C hasn't really been
modernized that much, and because Microsoft has been so slow to fully support
even just C99, let alone C11 or any GCC/clang extensions, often one has to to
stick to a subset of C99 anyways -- exactly as you surmised.

The problem with C is that it's extremely dangerous. Besides learning how to
program in C, you'll really want to know how to use memory debuggers such as
valgrind and Dr. Memory
([https://www.drmemory.org/](https://www.drmemory.org/)), as well as AFL for
fuzzing, and various GCC and clang sanitizers. You'll really want to let
functional programming language experience inform your approach to C API
design and implementation.

~~~
pjmlp
Microsoft hasn't been slow, they have been quite clear, C is legacy on
Windows, given its security implications, all new code should be C++ and the
compiler is called Visual C++ after all.

C support is done to the extent of ISO C++ requirements.

For those that still want to use plain old C on Windows, they have contributed
to clang, and it is now available as part of Visual Studio installer.

------
bane
The most important difference between a higher level language and C is that
you really _have_ to understand a bit about the underlying hardware
architecture to do it "right". C is a fairly thin veneer over assembly and it
helps to have that mental model in mind when working in it.

It's a very small language with almost no batteries included, built very much
around the manipulation of pointers and memory more than just about anything
else.

To do C the "right" way means approaching problems from that perspective and
building mountains out of toothpicks while thinking about how the billions of
toothpicks need to interact with one another so they don't crash/catch
fire/etc.

------
WalterBright
I'd just type in the examples from K+R, try them out, and modify them to do
new things.

~~~
wiredfool
K+R is pretty ancient.

~~~
saagarjha
That doesn't make it worthless; it's still probably the best book to learn C
today if supplemented correctly.

------
vocram
Becoming proficient in a language usually involves: \- writing code with it
long enough, \- collaborate in a project based on it, \- reading code other
people wrote, \- keep yourself up to date by following the language evolution,
\- go more in depth in language internals, compilers, etc...

I wrote C for 10+ years (mostly bare metal FW), yet I am still amazed of how
little I know about it. Recently for example I learnt of all the things the
dynamic linker does in Linux, how symbols memory addresses are resolved at
runtime using PLT, ....

The good point about C is that it can be used for very different kind of
projects, so the choices are a lot.

~~~
stiray
This was a pure satisfaction when I have first seen it :)

[https://en.wikipedia.org/wiki/Duff%27s_device](https://en.wikipedia.org/wiki/Duff%27s_device)

~~~
saagarjha
(Please don't write code like this anymore)

~~~
stiray
Sure, duff device is obsolete due to cpu zero overhead looping but it is still
nice to see, mind boggling piece of code. :)

------
6c696e7578
The C FAQ used to be a good place to start. Note, _used_ to be:

[http://c-faq.com/](http://c-faq.com/)

What did you want to do on Windows? I think this depends as much on the
compiler as the code.

~~~
camgunz
Second this. Read it all more than once; the insights it will give you into C
are so valuable.

I'll also recommend C++ FQAs [1]. It's C++, yeah, but it's relevant to C in
many places, and since a lot of systems programming now uses C++ as the lingua
franca, it's a good, entertaining resource.

1: [http://yosefk.com/c++fqa/](http://yosefk.com/c++fqa/)

------
thefourthchime
I would read K&R, it’s a right of passage. Look at some of the larger open
source projects for how to organize and manage a large c project.

And practice pointers. Get really comfortable with how memory works.

------
springogeek
Programming in C requires you to take proper responsibility for what you
write, but also allows for great power in return.

I've been working on a reasonably large (and cross platform) project in C
([https://domeengine.com](https://domeengine.com)) for a couple years now, and
I find that C generally requires a certain kind of discipline. When you
interact with an API, you need to read the docs, figure out their specific
preconditions, and requirements on handling frees, establishing what you own
and what you don't.

It also helps to make sure that if you allocate something, you clean up after
in a clear and well defined way.

You should also get very familiar with debuggers (LLDB/GDB) and other dev
tools, to help when you have made a mistake.

In the modern era, you have a couple of options for getting it to run on
Windows. C89 using Visual Studio, The MSYS2/MinGW2 gcc toolchain, or a gcc
toolchain using the WSL. I use the MSYS2 tools for DOME because it requires
the fewest platform-specific modifications to my code, but this varies by
usecase.

------
fergie
Pretty obvious answer, but for those who are new to C, the C Programming
Language by Brian Kernighan and Dennis Ritchie is a good place to start

~~~
saagarjha
Best paired with a bunch of modern resources about how undefined behavior
works.

------
bryanwb
An important question to ask yourself is why do you want to learn C? If you
want to be able to read large C codebases makes sense. But if you want to
write embedded software or systems software, rust or c++11 (ugh) are arguably
a better place to start. I say this as someone who has learned C but moved on
to c++ without regrets. Though I have serious rust envy :)

~~~
rochak
What is stopping you from getting into Rust?

~~~
bryanwb
My current work projects require c++ unfortunately. Some day. Sigh

------
jerrysievert
while not a definitive guide,
[https://matt.sh/howto-c](https://matt.sh/howto-c) is a good example of how to
approach "modern" c.

c99 is fully implemented in windows with msvc (2015), gcc, clang, and intel's
compiler, so "right way" should not need to involve c89. most are c11
compliant as well.

------
m0rphling
If you're into visual/interactive learning, please give Harvard's CS50 a try.

[https://www.youtube.com/channel/UCcabW7890RKJzL968QWEykA](https://www.youtube.com/channel/UCcabW7890RKJzL968QWEykA)
[https://cs50.harvard.edu](https://cs50.harvard.edu)

------
vbtemp
First step is making sure you're using the flags

`-Wall -Werror -pedantic` and then one of `-std=c89` or `-std=c99`

(Or equivalent in whatever Windows C compiler)

~~~
giomasce
Why would you suggest older versions?

------
LocalMan
I've written many tens of thousands of lines of C, but retired 15 years ago.
The two best books I know are:

1\. C: A Reference Manual, by Harbison and Steele.
[https://www.amazon.com/Reference-Manual-Samuel-P-
Harbison/dp...](https://www.amazon.com/Reference-Manual-Samuel-P-
Harbison/dp/013089592X/ref=dp_ob_title_bk)

2\. The C Puzzle Book, by Alan Fueur. [https://www.amazon.com/Puzzle-Book-
Alan-R-Feuer/dp/020160461...](https://www.amazon.com/Puzzle-Book-Alan-R-
Feuer/dp/0201604612)

Harbison and Steele has much better explanations than K&R. The Fueur book
taught me a lot about C declarations. Declarations are that part of C language
that is them most unnecessarily difficult.

You asked about a slightly different question, best practices. But in the real
world you'll run into a lot of code that practices below that level.

------
haolez
I would focus on sources that use C11 or C18, since there are some niceties in
the newer standards.

As a reference, I like QEMU's source code[1]. It's huge, but the style and
practices found in any file will help you get a grip on good C.

[1] [https://github.com/qemu/qemu](https://github.com/qemu/qemu)

------
master_yoda_1
This is a fun book to start with "Expert C Programming Pete van Linden"
[https://www.amazon.com/Expert-Programming-Peter-van-
Linden/d...](https://www.amazon.com/Expert-Programming-Peter-van-
Linden/dp/0131774298)

------
johnisgood
In Modern C (book mentioned by OP), there is takeaway 2.11.1.14 which says
"Don't use NULL" because:

The definition in the C standard of a possible expansion of the macro NULL is
quite loose; it just has to be a null pointer constant. Therefore, a C
compiler could choose any of the following for it: 0U, 0, '\0', 0UL, 0L, 0ULL,
0LL, or (void * )0. It is important that the type behind NULL is not
prescribed by the C standard. Often, people use it to emphasize that they are
talking about a pointer constant, which it simply isn’t on many platforms.
Using NULL in a context that we have not mastered completely is even
dangerous. This will in particular appear in the context of functions with a
variable number of arguments.

NULL hides more than it clarifies. Either use 0 or, if you really want to
emphasize that the value is a pointer, use the magic token sequence (void * )0
directly.

[https://www.gnu.org/software/libc/manual/html_node/Null-
Poin...](https://www.gnu.org/software/libc/manual/html_node/Null-Pointer-
Constant.html) says:

The preferred way to write a null pointer constant is with NULL. You can also
use 0 or (void * )0 as a null pointer constant, but using NULL is cleaner
because it makes the purpose of the constant more evident.

If you use the null pointer constant as a function argument, then for complete
portability you should make sure that the function has a prototype
declaration. Otherwise, if the target machine has two different pointer
representations, the compiler won’t know which representation to use for that
argument. You can avoid the problem by explicitly casting the constant to the
proper pointer type, but we recommend instead adding a prototype for the
function you are calling.

[https://man.openbsd.org/style](https://man.openbsd.org/style) says:

NULL is the preferred null pointer constant. Use NULL instead of (type * )0 or
(type * )NULL in all cases except for arguments to variadic functions where
the compiler does not know the type.

\---

Readers: what is your take on it and why?

~~~
clarry
> Readers: what is your take on it and why?

It's ok to draw a line on what implementations you care about. And honestly,
at this day and age, I couldn't care less about implementations that define
NULL to be 0 (or something else that isn't a pointer). It's a case of where
it's not worth everyone's time to be catering for the lowest common
denominator.. instead, fix that implementation or just go download a better
one.

If I could make breaking changes to C today, I would remove the NULL macro and
replace with a lowercase null (or nil or whatever) keyword a definition that
doesn't impose pointless burden on its users.

That said, I'm still very much in the habit of casting NULL to void* when I'm
using it as an argument for variadic functions. It's silly, but that's just
how we do things...

~~~
mrr54
You could make a proposal to the C committee to add a keyword `_Nullptr` and
to add a header `stdnull.h` which has `#define nullptr _Nullptr`, like they
did with bool.

~~~
clarry
Yep. I'd be happier to work with the C committee if they were a little more
open. For example, their mailing list could be public.

------
msaqib8181
I think you can use any version of Visual studio to write C programs. I
recently did a video tutorial using Visual Studio:
[https://www.youtube.com/watch?v=JaDzgmZvY00](https://www.youtube.com/watch?v=JaDzgmZvY00)
on the "C++ Modulus Operator" [https://www.mycplus.com/tutorials/cplusplus-
programming-tuto...](https://www.mycplus.com/tutorials/cplusplus-programming-
tutorials/the-c-modulus-operator/)

------
Foobar8568
I am currently relearning C, I tried different books over the years (to not
say decades), never did more than a toy project. The book I picked up this
time was extreme c (from Amazon reviews, failry new book), by Kamran Amini,
and so far (few chapters in) it's fairly enjoyable as it takes C, compilation
process etc from the "basics", fairly hands-on and not too much theorical and
relatively fast paced. I feel that the book is more about how to make a
program C and not teaching literally the language itself. So really what I
needed.

------
_benj
I’m currently learning C myself and something that I realized is that often
the hard part to learn is not C the language but the domain in which is being
used.

For example, I’m trying to learn Linux drivers or embedded programming and I
thought that I’d find in a C book information about registers and such, but
registers don’t really belong to the C domain but to the hardware domain.

Thus, maybe find a way to clarify what you want to use C for and then learn
those domain problems and how C solves them.

------
enesunal
Essential parts of C language are actually really a small set.

What I'd _suggest_ is, learn syntax and try to understand linux kernel (which
is one of the very well crafted software piece we have written in C). If you
don't want to go that much of a deep dive, you can check sqlite source code as
well. Writing code starts with reading it. Do yourself a favour and spend more
time on reading code than reading books.

------
Paperweight
Perhaps better than a book, can anyone authoritatively point to a few small-
and-readable but best-in-class open-source C projects to use as a reference?

~~~
diego_moita
Lua and Sqlite sources are excellent.

~~~
elliotec
Linux as well. The comment culture of C devs really help with understanding
all of it.

~~~
mlvljr
There was a book featured in a HN post about a year ago - an older Linux
source with extra commentary, used by students in China, I think (book is in
English)

------
justforfunhere
All the advice already here is very good and implementable.

Here are my two cents.

I have been programming in C professionally for the past 12 years, and I think
the way to go would be to go implement a well known tool in C and then compare
your code with the open source code of that tool. e.g. Git.

You will learn a lot from how the feature that you chose to implement in a
certain way was implemented in a completely different way for various reasons.

------
guerrilla
It's not easy. The obvious answer is read and write lots of code. Experiment.
Make sure you actually know how a computer works. Learning some assembly even
if you don't ever use it can help with that (free ebook "Programming from the
Ground up" can be done in a weekend) Read existing code bases, different
styles, like linux or some GNOME stuff.

------
makach
Finding "the right way" is closer to religion than it is to problem solving
and science.

You will always be vulnerable to criticism and other people's opinions, and
you need to open up and acknowledge this fact and work with that. There are
best practices and principles you can adhere to. Stand up for your design
decisions, and refactor when you have to.

------
makz
I'd say there's no proper way. Every project has its way of writing C. With
the use of macros, sometimes it looks a bit like a DSL for every specific
project.

My advice: think about what kind of software you want to write and look for
similar projects, libraries, or contribute with a new module, functionality,
adapt something to your needs...

~~~
pritovido
I would advice AVOID C macros at all cost. They are so weak and hard to debug
and problematic.

I write in several languages and read lots of C projects made by others and
find the affirmation hard to believe: C is so simple that is very easy to read
if the writer of code has a minimum of competency.

You can say that of projects like C++, specially things like C++11 that are
languages by committee so complex that you can affirm that every C++
programmer is different or find programmers that could not understand each
coder's code. Not so with C.

That happens to me with C++ and lisp code. It takes a while for me to
understand what the author uses(or abuses) before being able to understand the
code. That does not happen with C code.

~~~
mrr54
The Linux kernel uses lots of macros, many of them with lowercase names that
are barely distinguishable from function names. Given the quality of that
codebase, I think not using macros is a bit silly.

------
jennyyang
Get code reviews from someone that actually knows C. Mentorship and harsh code
reviews are the best way to learn.

------
drran
I use C since 1992, but I never confident in my C code, unless it heavy with
macros to check error codes and return early, register memory allocations and
free memory at return, and so on. Rust improved my confidence in C code a lot,
but it looks more like Rust code now.

------
stephc_int13
In my opinion, one of the main reasons C looks old and not practical to
beginners is the standard libs API.

But it is perfectly possible to use C as a language with a more modern and
easier to read API, but you'll probably have to build your own.

------
Nursie
There are other compilers for windows than MSVC++, so you can move beyond C89
if you wish.

stdint.h is useful and should be required reading. I still come across too
many C projects that reimplement it poorly.

Learn to use valgrind, and maybe ddd too.

------
jfkebwjsbx
You can compile with clang on Windows, so you can use later standards.

------
aWidebrant
The main thing that C provides over other languages is direct hardware access.
So study the hardware, find out what you want to do with it, then use C to
implement it.

------
iRobbery
Besides all that is mentioned already to read or do. I would suggest to try
writing something you coded in python or go previously in C.

------
ajb
Read John Regehr's blog, eg
[https://blog.regehr.org/archives/213](https://blog.regehr.org/archives/213)

Read "Who Says C is simple?": [http://cil-
project.github.io/cil/doc/html/cil/](http://cil-
project.github.io/cil/doc/html/cil/)

Take up a different language :-)

------
gjkood
To start with, "The C Programming Langauge", Kernighan & Richie (K & R) [1].
Find the latest edition that you can buy.

I think the primary topic to master in C is pointers. This is where most
falter. It takes a few years to "master" (if we ever do). Here I would
recommend "Understanding and Using C Pointers", Richard Reese. [2]

If you are interested in networking, any of the classic "TCP/IP Illustrated
Vols I/II/III", W. Richard Stevens, [3] contain a ton of C code to implement
components of TCP/IP.

If you are interested in Graphics, then "Graphics Gems", Andrew Glassner [4]
is a good source.

"An Introduction to GCC", Brian Gough, [5] to understand the tooling and its
various bells and whistles.

My learning swimming by jumping into the deep end of the pool experience was
realized by learning Windows Programming using the Charles Petzold book and
navigating through Microsoft Foundation Classes in the late 80s/early 90s. The
state of the art in tooling wasn't that great in those days and I spent months
with the book to get things going. This was done after I had built a
foundation with K&R and a decent amount of Unix network programming.

I see a lot of the other posts recommend more modern books. But you still need
to build your foundation on C and Pointers in particular.

Good luck on your journey.

[1] [https://www.amazon.com/Programming-Language-2nd-Brian-
Kernig...](https://www.amazon.com/Programming-Language-2nd-Brian-
Kernighan/dp/0131103628/ref=sr_1_1?crid=2FEGL0ITD7BO&keywords=the+c+programming+language&qid=1583705302&sprefix=The+C+Progra%2Caps%2C212&sr=8-1)

[2] [https://www.amazon.com/Understanding-Using-Pointers-
Techniqu...](https://www.amazon.com/Understanding-Using-Pointers-Techniques-
Management/dp/1449344186/ref=sr_1_2?crid=32I1T4I421WPZ&keywords=understanding+and+using+c+pointers&qid=1583705390&sprefix=Understanding+and+Using+C+P%2Caps%2C221&sr=8-2)

[3] [https://www.amazon.com/TCP-Illustrated-Protocols-Addison-
Wes...](https://www.amazon.com/TCP-Illustrated-Protocols-Addison-Wesley-
Professional/dp/0321336313/ref=sr_1_1?crid=V0LZ9TYHEOFS&keywords=tcp%2Fip+illustrated&qid=1583705448&sprefix=TCP%2Fip+%2Caps%2C222&sr=8-1)

[4] [https://www.amazon.com/Graphics-Gems-Andrew-S-
Glassner/dp/01...](https://www.amazon.com/Graphics-Gems-Andrew-S-
Glassner/dp/0122861663/ref=sr_1_1?crid=1WEA9UYLALBRE&keywords=graphics+gems&qid=1583705599&sprefix=Graphics+Ge%2Caps%2C212&sr=8-1)

[5] [https://www.amazon.com/Introduction-GCC-GNU-
Compilers/dp/095...](https://www.amazon.com/Introduction-GCC-GNU-
Compilers/dp/0954161793/ref=sr_1_1?crid=1L8K7ERCL07RZ&keywords=an+introduction+to+gcc&qid=1583705516&sprefix=introduction+to+GCC%2Caps%2C218&sr=8-1)

------
vineel567
I am in the same boat as you are...bare with me by no means I am an expert.

In fact, I read couple of chapters in Modern C yesterday :). Here are some of
the things I am doing to improve my C skills to match with some of the
admired/professional developers.

Decide which platform to use

~~~~~~~~~~~~~~~~~~

Unfortunately, to become proficient in it we need to write code and focus on a
platform. I have been fighting between whether to develop on Windows vs Linux.
I am very experienced in Windows environment(using debuggers/cl/linkers/Windbg
etc) but when it comes to writing good quality C code(not C++) and for
learning how to write good maintainable moderately large source code, my
research showed that Windows compilers/C standard APIs are not great, in fact
they hinder your productivity. I have wasted countless number of hours to just
figure out how to properly create a simple C project with a decent build
system. Unfortunately, I could not find one. The closest I could find is CMake
as MSBuild is a nightmare to work with. I even tried NMAKE but failed. When it
comes to documentation of finding basic C Api usage,
MSDN([https://docs.microsoft.com/en-us/cpp/c-runtime-
library/run-t...](https://docs.microsoft.com/en-us/cpp/c-runtime-library/run-
time-routines-by-category)) does a decent job. But in the name of security you
will find zillion variations( __s,_ _l) of an API and by default msvc compiler
will not let you use some of the API in their simple forms. Instead, you have
to define _CRT_SECURE_NO_WARNINGS etc. I think for someone just getting
started to develop/learn to write a decent code base in C these restrictions
really hinder the productivity. So finally, I have decided to instead focus my
learning on Linux platform(currently through WSL - Windows subsystem for
Linux) with its POSIX apis. You know what, `man 3 printf` or `man 3 strlen` is
soooooo much better than googling msdn

Mastering C

~~~~~~~

I think, the simple and straight answer here is reading good code and writing
"good" code and also reading good C content(be it books or articles). I think
these are the three ingredients necessary to get started. Of all the open
source projects that I have investigated, I found Linux Kernel and related
projects seems to have very good taste in terms of code quality. Currently, I
am just focused how they use the language rather than what they actually do in
the project. Things like, how they structure the project, how they name
things, how they use types, how they create structures, how they pass
structures to function, how they use light weight object based constructs, how
they handle errors in function(for example forward only goto exits), how they
use signed/unsigned variables etc(more of my learnings to the end), how they
use their own data structures. I think its good to initially focus/target on
ANSI C API with C99 instead of heavily relying on the OS specific API on which
ever platform you choose. For example, such projects could be writing binary
file parsers for example projects like .ISO file format etc.

Good C projects/articles

~~~~~~~~~~~~~~~

1\. Winlib.net -
[https://github.com/jcpowermac/wimlib](https://github.com/jcpowermac/wimlib)
is a great source of information

2\. e2fsprogs -
[https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/](https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/)

3\. MUSL - [https://git.musl-libc.org/cgit/musl/tree/](https://git.musl-
libc.org/cgit/musl/tree/)

4\. General C Coding Style -
[https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-
style.rst)

4\. [https://nullprogram.com/tags/c/](https://nullprogram.com/tags/c/) \-
great source of C knowledge

5\. CCAN -
[https://github.com/rustyrussell/ccan/tree/master/ccan](https://github.com/rustyrussell/ccan/tree/master/ccan)
\- great source of C tidbits from none other than Rusty Russell - I haven't
read all of them

6\. POSIX 2018 standard -
[https://pubs.opengroup.org/onlinepubs/9699919799.2018edition...](https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/)

continued in the comment....

~~~
vineel567
My Learnings(know your language/know your complier/know your tools)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1\. _t suffix is the notion used to denote a typedef for a given type /* This
example is from do_journal.c in e2fsprogs _/ struct journal_transaction_s {
... blk64_t start, end; ... }; typedef struct journal_transaction_s
journal_transaction_t;

2\. Know about headers like stddef.h and stdint.h and when they are supposed
to be used. for example: When to use normal data types like int vs int16_t
etc.

3\. From
[https://en.cppreference.com/w/c/types/integer](https://en.cppreference.com/w/c/types/integer)
we can sense that int_t_ are of exact width types which might have some perf
side effects if the underlying hardware does not support the width natively.

    
    
        For example, in visual studio x86/x64 we have typedef short int16_t; and
        typedef int int32_t; int_fast_t* on the other hand make sure a suitable
        width which maps natively to the available hardware type For example, in
        visual studio x86/x64 typedef int int_fast16_t; instead of typedef short
        int_fast16_t; size_t on the other hand alias to the natural unsigned word
        length of the hardware for example on x86 typedef unsigned int size_t; and
        on x64 typedef unsigned __int64 size_t;
    

4\. Know your compiler predefined standard macros On Microsoft compiler _WIN64
- defined when we are compiling for x64 code _WIN32 - defined when both x86
and x64 code is getting compiled _MSC_VER - defines which compiler version are
we using, indicate different visual studio versions __cplusplus - defined when
the translation unit is compiled as C++

5\. We can get a FILE* from HANDLE using below APIs from io.h and fcntl.h Fd =
_open_osfhandle((intptr_t)Handle, _O_TEXT); File = _wfdopen(Fd, L"r"); Once we
get the FILE* we can use fgets for line oriented string operations

6\. Learned about var args and aligned memory Aligned memory means the address
returned by the _aligned_malloc is always divisible by the alignment we
specify. For example: char _p = _aligned_malloc(10, 4); the address return in
p will be always be divisible by 4. We should also free the allocated memory
using _aligned_free(p)

7\. atoi(str) this api also processes input string until it can convert. For
example atoi("123asda") will still give 123 as the return result. Any
whitespace in the beginning of the input string will be ignored. So atoi("
123asd") will still return 123. It is recommended to use strto_ functions to
convert strings to int/long/float types as they also can return pointer to the
character which is a non integer

8\. UCRT support around 40 POSIX system level APIs but most of these have _
prefix to them. wimlib in wimlib_tchar.h defines #define topen _open for Win32
and #define topen open for POSIX systems The take away here is the UCRT
implementation even though differ in name the parameters are exactly the same.

    
    
        For example:
          UCRT Win32: int _open(const char *filename, int oflag, int pmode);
          POSIX:      int  open(const char *pathname, int flags, mode_t mode);
    

9\. We can install only build tools(VC compiler) excluding IDE from
[https://aka.ms/buildtools](https://aka.ms/buildtools)

10\. Best video on C Standard and some of its less known features - "New"
Features in C - Dan Saks Year C Standard Comments 1983 C standard committee is
formed 1989 C89 C89 US standard 1990 C90 C89 International Standard 1999 C99
C99 Standard 2011 C11 C11 Standard 2018 C18 C18 Bugfix release

    
    
        _reserved - Reserved for global scope. But we can use any identifier with an
        _ as a local variable or a structure member
    
        __reserved - Always reserved. Meaning the user program should not use any
        variable with two underscores __
    
        _Reserved - Always reserved. Meaning the user program should not use any
        variable with an underscore and capital letter.
    
        This is the reason why _Bool is named that way to prevent breaking existing
        bool typedef used in existing code.
    

11\. Another good video on lesser known C features - Choosing the Right
Integer Types in C and C++ - Dan Saks - code::dive 2018

    
    
        we can use CHAR_BIT from limits.h instead of 8 for example when you want to
        print the bits in a integer, we can do below `for (size_t i = sizeof(int) *
        CHAR_BIT; i >= 0; i--) {...}`
    

12\. size_t denotes the native architecture supported natural word size. So
for 32bit it is 4 bytes unsigned quantity and for 64bit it is 8 bytes unsigned
quantity. Hence it is defined as follows

    
    
        #ifdef _WIN64
            typedef unsigned __int64 size_t;   //8 bytes on x64
        #else
            typedef unsigned int     size_t;   //4 bytes on x86
        #endif
    
        where as uintmax_t denotes the maximum integer type that is available in the
        language. So on a 32bit you could still represent a 64 bit quantity using
        long long even though it not what the architecture directly maps to. So
        below is how it is defined in both x86 and x64
    
        typedef unsigned long long uintmax_t;  //in MSVC both x86 and x64 support 64
        bit quantities using long long. So size_t does not give us the maximum
        unsigned integer, instead it gives us the native unsigned integer i.e., on
        x86 it will be 32bits and on x64 it is 64bits. So recommendation is to use
        size_t where ever possible instead of using int. for example.
    
        int len = strlen(str); // not recommended because on both x86 and x64 of MSVC int is 4 bytes due to LLP64
        size_t len = strlen(str); // recommended because size_t will automatically maps to 4 bytes in x86 and 8 bytes in x64
    

13\. C11 introduced the concept of static asserts. These are basically
conditional asserts which can be evaluated during compile time. So C11 has a
new keyword called _Static_assert(expr, message) The reason for this ugly name
is the same idea of not to break existing code. so for convenience assert.h
header provides static_assert macro which mean the same. One of the use of
static asserts is below

    
    
        struct book {
          int pages;
          char author[10];
          float price;
        };
    
        static_assert(sizeof(struct book) == sizeof(int) + 10 * sizeof(char) + sizeof(float),
                      "structure contains padding holes!");
    

14\. Another good video on some low level details - Storage Duration and
Linkage in C and C++ - Dan Saks

15\. #define _CRT_SECURE_NO_WARNINGS can be used to disable CRT warning for
common functions.

16\. Any ucrt function which begins with _ is a non standard api provided by
ucrt. For example in string.h's _strdup, _strlwr, _strrev are some. The take
away here is, it is easy to identify which function is part of C standard and
which are not. Interestingly some(not all) of these non standard functions are
part of posix so in glibc(which implements posix) don't have _ in them.

17\. All posix function in posix standard with [CX] annotation indicate
Extension to the ISO C standard for example, below function from stdlib.h is
posix extension. UCRT defines a similar api called _putenv, since this is not
part of C standard, UCRT version has an _

    
    
        stdlib.h - posix
        [CX] int setenv(const char *, const char *, int);
        stdlib.h - ucrt
        int _putenv( const char *envstring );
    
        stdio.h - posix
        [CX] int fileno(FILE *);
        stdio.h - ucrt
        int _fileno( FILE *stream );
    

18\. Learned about CGold: The Hitchhiker’s Guide to the CMake. An awesome
tutorial about CMake. Now it is super easy to start a C project without
worrying about the individual build systems.

    
    
        # CMakeLists.txt - minimum content
        cmake_minimum_required(VERSION 3.4)
        project(command_line_parser)
        add_executable(command_line_parser main.c)
    
        # commands to run to generate the respective native build files like vcxproj files
        # In below command -S standards for source directory path.
        # -B stands for final directory where vcxproj files are generated
        # CMake only generate one flavor (x64/x86) per project file, here we are generating x64 by specifying x64
        cmake -S . -B builds -G "Visual Studio 16 2019" -A x64
        # we can also use cmake-gui to do the above
    
        # Once vcxproj files are generated we can either directly build the proj files using Visual Studio
        # or better use cmake itself to build it for us from CMD using msbuild
        cmake --build builds
    
    
    

Hope these help.

~~~
saagarjha
> _t suffix is the notion used to denote a typedef for a given type /* This
> example is from do_journal.c in e2fsprogs / struct journal_transaction_s {
> ... blk64_t start, end; ... }; typedef struct journal_transaction_s
> journal_transaction_t;

This is undefined behavior in POSIX.

~~~
clarry
And

    
    
        unsigned total(unsigned a, unsigned b) { return a + b; }
    

is undefined behavior in C.

------
tedunangst
Radical suggestion: read the C standard.

~~~
kevindong
Asking someone to read a multi-hundred page standards document just to learn
the language is wholly unreasonable.

~~~
clarry
Well, OP asked for source of truth. Nothing comes as close as the standard
itself.

Honestly, I think any programmer writing C today should have it around for
reference. And yeah you kinda need to read it too, or you won't be able to
refer much.

That said, no need to read it cover to cover. There's stuff one can earmark as
being there but ignore until it's actually needed (for example: the grammar
and all the library functions).

And speaking of _tedu_ , I would recommend to the OP that they get in the
habit of checking out the OpenBSD man pages for libc functions.

~~~
sramsay
I actually have very few $200 PDFs lying around.

Do you really go purchase the standard documents from ISO? Or does your
employer? I'd love to have the actual standard "around for reference," but
700-page technical documents from ISO are not cheap.

~~~
clarry
The next best thing is the latest draft standards, which are available online
for free (and I always have them on my laptop, PC, and personal server).
Differences between them and final official standard are not important. Search
for N1256, N1570. Or grab them here. [http://www.open-
std.org/jtc1/sc22/wg14/www/standards](http://www.open-
std.org/jtc1/sc22/wg14/www/standards)

(There are more readable html versions floating about)

------
LessDmesg
Screw C, really. Let this crappy old language die off quietly. Learn Zig (the
best replacement for C) or at least Rust.

------
ryan-allen
I'd check out Zed Shaw's book [0]. It's opinionated, but I think that's a good
thing for something like C.

It's broken up into exercises that you start working through straight away,
and you start early with valgrind.

[0] [https://learncodethehardway.org/c/](https://learncodethehardway.org/c/)

~~~
saagarjha
The author of that book doesn't really like C, and it shows. And valgrind is
usually not the first tool you should be using to debug memory issues–try
Address Sanitizer instead.

------
PureParadigm
C is great for learning about how computers work at a low level. In my
college, we started by writing a simple compiler. This should force you to
understand pointers and memory which, as others have mentioned, are
fundamental. You'll have to both know how the assembly works and to write
correct C code. So writing a simple compiler will force you to understand it
two different ways at once. My opinion is you'll learn more by diving in and
doing things, especially with your existing programming background.

But, for your own sanity and everyone else's, do not start new projects in C!
(Aside from purely academic ones for you to learn.) The point of a programming
language is to help humans write safe and correct code. In this sense, C has
completely failed. The syntax itself is just begging you to make a subtle
mistake. And due to lack of memory safety, even the most well tested and
scrutinized projects in C/C++ (such as Chromium) suffer from buffer overflows
or memory leaks, potential security vulnerabilities that are automatically
prevented by design in other languages. If you need to do something low level
with any sort of confidence, use a memory-safe language like Rust, which can
even do interop with existing C libraries and code.

(Edit: typo)

~~~
bronipstid
It depends on what you're doing. Low level stuff pretty much has to be C. But
for applications I agree there are much better alternatives these days.

~~~
PureParadigm
Yeah, there may be some situations where C is necessary as a wrapper for
assembly if you're _extremely_ memory constrained or something like that. But
I wouldn't have any confidence in it working as intended unless it's dead
simple.

