How do I call windows apis in GCC inline ASM

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C++

ASM

API

GCC

hi all

i want to learn asm inlining using codeblocks+GCC(MinGW32) and i came across this problem.
this is my code:

#include <iostream>
#include <Windows.h>
#include <winuser.h>

char * msg = "Hello, World!\n";
char * wMsg = "Content of the window..";
char * wCaption = "Window title";

int main (){
  std::cout << "before call" << "\n";

   asm(
"movl _msg,%eax\n\t"
"pushl %eax\n\t"
"calll _printf\n\t"
"popl %eax\n\t"
"movl $0, %eax\n\t"
"movl _wCaption, %ebx\n\t"
"movl _wMsg, %ecx\n\t"
"movl $0, %edx\n\t"
"pushl %eax\n\t"
"pushl %ebx\n\t"
"pushl %ecx\n\t"
"pushl %edx\n\t"
"calll MessageBoxA\n\t"
"popl %edx\n\t"
"popl %ecx\n\t"
"popl %ebx\n\t"
"popl %eax\n\t"
      );

    std::cout << "after call" << "\n";
}

and when i want to compile, i get:

undefined reference to `MessageBoxA'

i think its config related; because when using MinGW64, this below code compiles just fine:

#include <iostream>

char * msg = "Hello, World!\n";
char * wMsg = "Content of the window..";
char * const wCaption = "Window title";

char * const wCaption222 = "Window title";

int var = 0;


int main (){
  std::cout << "before call" << "\n";


   asm(
    "movq $0, %%rcx\n\t"
    "movq %2, %%rdx\n\t"
    "movq %4, %%r8\n\t"
    "movq $0, %%r9\n\t"
    "callq MessageBoxA\n\t"
    : "=r" (var)
    : "r" (msg), "r" (wMsg) , "r" (wCaption), "r" (wCaption222)
    : "cc");

    std::cout << var << "\n";
    std::cout << "after call" << "\n";
}

i used "msys2-x86_64" to install MinGW32 and 64 and then set the directories in code blocks (creating two compiler profiles); so i don't know if messed up anything or its MinGW32's fault.

What I have tried:

googling, including various headers