Build DLL in MinGW/MSYS2 without declspec(dllexport)

Question

Is there any way to compile a Windows DLL in MinGW/MSYS2 with the desired exported symbols without annotating the source code with _declspec(dllexport)?

Answer 1

You probably already solved the problem, it has been over a year, but other people might have this problem, so:

Yes in MinGW you don't have to add the declspec(dllexport) and a good reason might be that you just want to use someone else's library source without modifying/forking it.

Here is an example lib.c that will be compiled into a DLL and exporting func with the Makefile below:

int func(int A) {
    return A*2;
}

And a lib.h for usage in the executable:

typedef int func_type(int A);

The Makefile, but make sure that you fix the indentation: the two indented lines need a tab instead of 4 spaces:

all: lib.dll ex.exe

lib.dll: lib.c
    gcc -o lib.dll -shared lib.c -Wall

ex.exe: ex.c
    gcc -o ex.exe ex.c -Wall

Note that the -shared is, what makes the output into a valid DLL and makes it export func.

Example ex.c for testing purposes:

#include <stdio.h>
#include <windows.h>
#include <assert.h>
#include "lib.h"
int main(void) {
    void* Lib = LoadLibraryW(L"lib.dll");
    assert(Lib);
    func_type (*func) = (func_type*)GetProcAddress(Lib, "func");
    assert(func);
    printf("%i\n", func(11)); // should output 22
    return 0;
}