All Questions
9
questions
0
votes
1
answer
52
views
Expressing a pointer to a const function
In C, I can express a pointer to a const function like this:
typedef void fun_t(void);
const fun_t *fp;
(I don't know if the type of fp has any practical use, but it is a real and distinct type; e.g.,...
- 808
0
votes
2
answers
113
views
Consolidating GNU C's and C23's deprecated function attribute
The problem I am facing when using the below macro
// Assume that __GNUC__ or __clang__ is defined.
#if defined(__has_c_attribute)
#if __has_c_attribute(deprecated)
#define ...
- 7,235
36
votes
2
answers
3k
views
Why isn't the keyword false an integer constant expression in gcc C23?
Latest gcc 13.x (trunk) gives a compiler error (gcc -std=c23) for this code:
int* p = false;
error: incompatible types when initializing type 'int *' using type '_Bool'
How can this be correct?
C23 ...
- 208k
2
votes
2
answers
184
views
Plain C equivalent to Rust's unimplemented!() macros
Please note that this is not a question on C++, but on plain C
In Rust there is a handy macro unimplemented!() to let the runtime crash, to be used when a function is unimplemented.
I basically have ...
- 3,261
7
votes
1
answer
200
views
Why doesn't gcc 13 display the correct binary represenation?
While answering a question here, I made the following example:
#include <stdio.h>
#include <math.h>
int main (void)
{
float_t a = -248.75;
printf("%f\n", a);
unsigned ...
- 208k
2
votes
2
answers
2k
views
gcc: constexpr functions in C23?
Playing around with constexpr with GCC v14.0 (which should be close to the soon to be released GCC v13.1), I compiled the following module:
constexpr int f (int x)
{
return x + 2;
}
constexpr ...
- 3,553
0
votes
2
answers
474
views
Regarding mainstream compilers and int main(){} in C23
My program:
int main(){}
In upcoming C23, non-prototype and "K&R style" functions are removed. I realize that C23 is not yet formally released, but the current behavior of gcc and clang ...
- 208k
3
votes
1
answer
1k
views
Looking for stdckdint.h in the gcc 11.2 collection
I'm trying to find a copy of stdckdint.h, which I assume should be in the gcc 11.2 collection, but a search fails to locate it in the downloaded source tarball.
Is it not public yet, or do I have to ...
- 1,657
3
votes
1
answer
503
views
Is [[nodiscard]] any different from [[gnu::warn_unused_result]]?
I had some code that used the GCC extension [[gnu::warn_unused_result]] (a.k.a. __attribute__((__warn_unused_result__))). Now I attempted to use C2x's [[nodiscard]] and I got an incomprehensible ...
