I saw the new feature called ImportC, it's cool to be able to use C code/libraries, but I'm not much experience in C and didn't understand this incomplete documentation: https://dlang.org/spec/importc.html
How to use ImportC?

On Thursday, 3 March 2022 at 19:05:22 UTC, Leonardo wrote:

You just add the C files like D files when you compile and import them in your D code as you would a D module. At least that is all I've been doing. Simple example:

foo.c:

double twice(double x) {
  return 2.0*x;
}

program.d:

import foo;
import std.stdio;

void main() {
  writeln(twice(6.8));
}

Compilation:

dmd program.d foo.c

Thanks but not worked here.

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Copyright (C) 1999-2021 by The D Language Foundation, All Rights Reserved written by Walter Bright
[leonardo@leonardo-pc dimportc]$ ls
foo.c  program.d
[leonardo@leonardo-pc dimportc]$ cat foo.c
double twice(double x) {
  return 2.0*x;
}
[leonardo@leonardo-pc dimportc]$ cat program.d
import foo;
import std.stdio;

void main() {
  writeln(twice(6.8));
}

[leonardo@leonardo-pc dimportc]$ dmd program.d foo.c
/usr/include/dlang/dmd/core/stdc/stdio.d(1256): Error: function `core.stdc.stdio.vfprintf` `pragma(printf)` functions must be `extern(C) int vfprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1259): Error: function `core.stdc.stdio.vfscanf` `pragma(scanf)` functions must be `extern(C) int vfscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1262): Error: function `core.stdc.stdio.vsprintf` `pragma(printf)` functions must be `extern(C) int vsprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1265): Error: function `core.stdc.stdio.vsscanf` `pragma(scanf)` functions must be `extern(C) int vsscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1268): Error: function `core.stdc.stdio.vprintf` `pragma(printf)` functions must be `extern(C) int vprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1271): Error: function `core.stdc.stdio.vscanf` `pragma(scanf)` functions must be `extern(C) int vscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1485): Error: function `core.stdc.stdio.vsnprintf` `pragma(printf)` functions must be `extern(C) int vsnprintf([parameters...], const(char)*, va_list)`

On Friday, 4 March 2022 at 01:30:00 UTC, Leonardo wrote:

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Copyright (C) 1999-2021 by The D Language Foundation, All Rights Reserved written by Walter Bright
[leonardo@leonardo-pc dimportc]$ ls
foo.c  program.d
[leonardo@leonardo-pc dimportc]$ cat foo.c
double twice(double x) {
  return 2.0*x;
}
[leonardo@leonardo-pc dimportc]$ cat program.d
import foo;
import std.stdio;

void main() {
  writeln(twice(6.8));
}

[leonardo@leonardo-pc dimportc]$ dmd program.d foo.c
/usr/include/dlang/dmd/core/stdc/stdio.d(1256): Error: function `core.stdc.stdio.vfprintf` `pragma(printf)` functions must be `extern(C) int vfprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1259): Error: function `core.stdc.stdio.vfscanf` `pragma(scanf)` functions must be `extern(C) int vfscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1262): Error: function `core.stdc.stdio.vsprintf` `pragma(printf)` functions must be `extern(C) int vsprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1265): Error: function `core.stdc.stdio.vsscanf` `pragma(scanf)` functions must be `extern(C) int vsscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1268): Error: function `core.stdc.stdio.vprintf` `pragma(printf)` functions must be `extern(C) int vprintf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1271): Error: function `core.stdc.stdio.vscanf` `pragma(scanf)` functions must be `extern(C) int vscanf([parameters...], const(char)*, va_list)`
/usr/include/dlang/dmd/core/stdc/stdio.d(1485): Error: function `core.stdc.stdio.vsnprintf` `pragma(printf)` functions must be `extern(C) int vsnprintf([parameters...], const(char)*, va_list)`

They must have introduced a bug. Works for me with DMD 2.098.0 and LDC 1.28.0. ImportC is under heavy development right now. Most of the 2.098.1 changelog was related to ImportC.

On Friday, 4 March 2022 at 01:30:00 UTC, Leonardo wrote:

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Please retry with the beta or nightly build. I think your bug was already fixed since 2.098.1.

On Friday, 4 March 2022 at 17:17:17 UTC, MoonlightSentinel wrote:

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Just had a chance to try this. Works with the beta.

On Friday, 4 March 2022 at 01:30:00 UTC, Leonardo wrote:

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Copyright (C) 1999-2021 by The D Language Foundation, All Rights Reserved written by Walter Bright
[leonardo@leonardo-pc dimportc]$ ls

...

LDC works with DMD fronted the same version v2.098.1

LDC - the LLVM D compiler (1.28.1):
based on DMD v2.098.1 and LLVM 13.0.1

On Friday, 4 March 2022 at 17:17:17 UTC, MoonlightSentinel wrote:

[leonardo@leonardo-pc dimportc]$ dmd --version
DMD64 D Compiler v2.098.1

Thank you all. In v2.099.0 it works.