Thread: Placing structs on header file

Hello! I'm trying to put a struct on a header file. Here is the code:

Code:

#ifndef _STRUCTS_H_
#define _STRUCTS_H_
#define MAX_SIZE 1000


typedef struct {
    
    char Name [MAX_SIZE];
    char Gender [2];
    int Age;
    
} pData;


#endif //_STRUCTS_H_

But whenever I compile the header file itself, I got an error:

Code:

C:\Program Files (x86)\Dev-Cpp\MinGW32\lib\libmingw32.a(main.o)    In function `main':91        e:\p\giaw\src\pkg\mingwrt-4.0.3-1-mingw32-src\mingwrt-4.0.3-1-mingw32-src\src\libcrt\crt\main.c    undefined reference to `WinMain@16'
C:\Users\USER\Desktop\PROG\C\Data Collector\collect2.exe    [Error] ld returned 1 exit status

What is "undefined reference to `WinMain@16'"?
And how can I successfully put my structs in a header file?

Thanks in advance!

You are trying to compile and link your code into a Windows executable. The compiler complains that it cannot find your WinMain function, which is the entry point to a Win32 (Windows) program. An executable program needs an entry point (WinMain for Windows apps and main for console applications). Your header file only contains definitions and needs not be compiled on its own. It would typically be included into your executable source (which would normally define the WinMain or main function) and the the preprocessor would copy its content at compilation time to produce a final executable object.

To fix your problem, create a c source (.c), include your header file and define either main or WinMain (depending on your target executable).