Create C header files from

[Dennis]

On Tuesday, 17 February 2026 at 15:27:20 UTC, MaxNaderer wrote:
> I have looked into __traits and I guess i need to go this way.

You can use traits, I've done something like that for Pascal 
instead of C. It roughly looks like:

```D
string headerFromDModules(modules...)()
{
	string result = "#pragma once\n";

	foreach (mod; modules)
	{
		foreach (mem; __traits(allMembers, mod))
		{
			static if (is(typeof(__traits(getMember, mod, mem)) == 
function))
			{
				alias F = __traits(getMember, mod, mem);
				static if (functionLinkage!F == "C")
				{
					result ~= functionToHeader!(mem, F);
				}
			}
		}
	}

	result ~= "\n";
	return result;
}
```

`string functionToHeader(string mem, alias F)()` then has to 
introspect Parameters!F, ParameterIdentifierTuple!F, 
ParameterStorageClassTuple!F, and ReturnType!F and generate a C 
string accordingly. It can be used like so:


```D
import pkg.a;
import pkg.b;

import std;

void main()
{
     File("header.h", "w").write(headerFromDModules!(pkg.a, pkg.b);
}
```

> The perfect way would be to get a XML or json from the 
> functions so that the bindings can be easily automated

dmd has the `-X` flag to generate JSON which I'd wager has 
sufficient information to generate C headers, but you can also 
open an enhancement request in the issue tracker 
(https://github.com/dlang/dmd/issues) to make dmd directly 
generate C headers because it sounds like a worthwhile feature.