I have a simple

dub.sdl

name "test"
targetType "executable"
buildOptions "betterC"

app.d

module test;
import core.stdc.stdio : fprintf, stderr;

extern(C) int main(string[] args)
{
	fprintf(stderr, "Test\n",);
	return 0;
}

When I'm trying to compile this on windows with latest dmd or ldc I get

test ~master: building configuration "application"...
Linking...
test.obj : error LNK2019: unresolved external symbol stderr referenced in function main
.dub\build\application-debug-windows-x86_64-dmd_v2.098.1-dirty-FB5231E74956BBA34BF960F450A8342C\test.exe : fatal error LNK1120: 1 unresolved externals
Error: linker exited with status 1120
C:\D\dmd2\windows\bin64\dmd.exe failed with exit code 1.

Works with dmd-2.091.0

Any idea what might be the problem here?

On Wednesday, 2 February 2022 at 03:34:29 UTC, forkit wrote:

Hi did not help

dub build --arch=x86_64

## Warning for package test ##

The following compiler flags have been specified in the package description
file. They are handled by DUB and direct use in packages is discouraged.
Alternatively, you can set the DFLAGS environment variable to pass custom flags
to the compiler, or use one of the suggestions below:

-m32: Use --arch=x86/--arch=x86_64/--arch=x86_mscoff to specify the target architecture, e.g. 'dub build --arch=x86_64'

Performing "debug" build using C:\D\dmd2\windows\bin64\dmd.exe for x86_64.
test ~master: building configuration "application"...
Linking...
test.obj : error LNK2019: unresolved external symbol stderr referenced in function main
.dub\build\application-debug-windows-x86_64-dmd_v2.098.1-dirty-ED981EB8716B85E9E2580186FAF4E89B\test.exe : fatal error LNK1120: 1 unresolved externals
Error: linker exited with status 1120
C:\D\dmd2\windows\bin64\dmd.exe failed with exit code 1.

On Wednesday, 2 February 2022 at 01:24:30 UTC, Abby wrote:

name "test"
targetType "executable"
buildOptions "betterC"

module test;
import core.stdc.stdio : fprintf, stderr;

extern(C) int main(string[] args)
{
	fprintf(stderr, "Test\n",);
	return 0;
}

test ~master: building configuration "application"...
Linking...
test.obj : error LNK2019: unresolved external symbol stderr referenced in function main
.dub\build\application-debug-windows-x86_64-dmd_v2.098.1-dirty-FB5231E74956BBA34BF960F450A8342C\test.exe : fatal error LNK1120: 1 unresolved externals
Error: linker exited with status 1120
C:\D\dmd2\windows\bin64\dmd.exe failed with exit code 1.

Yes, I have an idea, although not a Windows user. So look at the definitions i core.stdc.stdio:

else version (CRuntime_Microsoft)
{
    ///
    shared FILE* stdin;  // = &__iob_func()[0];
    ///
    shared FILE* stdout; // = &__iob_func()[1];
    ///
    shared FILE* stderr; // = &__iob_func()[2];
}

shouldn't these variable declarations be extern ?

On Wednesday, 2 February 2022 at 07:33:58 UTC, Basile B. wrote:

name "test"
targetType "executable"
buildOptions "betterC"

Try

module test;
import core.stdc.stdio : FILE, fprintf;

extern shared FILE* stderr;

extern(C) int main(string[] args)
{
	fprintf(stderr, "Test\n",);
	return 0;
}

to confirm if it is or not the extern problem

On Wednesday, 2 February 2022 at 07:51:07 UTC, Basile B. wrote:

name "test"
targetType "executable"
buildOptions "betterC"

module test;
import core.stdc.stdio : FILE, fprintf;

extern shared FILE* stderr;

extern(C) int main(string[] args)
{
	fprintf(stderr, "Test\n",);
	return 0;
}

missing extern(C), it should be:

module test;
import core.stdc.stdio : FILE, fprintf;

extern(C) extern shared FILE* stderr;

extern(C) int main(string[] args)
{
	fprintf(stderr, "Test\n",);
	return 0;
}