undefined reference to `WinMain@16' collect2.exe: error: ld returned 1 exit status

Question

I am using eclipse CDT to test the Intel instructions and below is my program:

#define cpuid(func,ax,bx,cx,dx)\
__asm__ __volatile__ ("cpuid":\
 "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));
int Check_CPU_support_AES()
 {
 unsigned int a,b,c,d;
 cpuid(1, a,b,c,d);
 return (c & 0x2000000);
 }

When I compile the above code, I get linkage error as:

Info: Internal Builder is used for build
gcc -O0 -g3 -Wall -c -fmessage-length=0 -o "src\\Intel.o" "..\\src\\Intel.c" 
gcc -o Intel.exe "src\\Intel.o" 
c:/mingw/bin/../lib/gcc/mingw32/4.7.2/../../../libmingw32.a(main.o):main.c:(.text.startup+0xa7): undefined reference to `WinMain@16'
collect2.exe: error: ld returned 1 exit status

Please help me regarding the issue.

Answer 1

you have to save the file first>> Ctrl + s

Answer 2

Your program isn't complete. You need to implement the OS-expected entry point. In your case, that looks like it's called WinMain.

Answer 3

Yes, Main () function is missing and the compiler is not able to find an entry point for executing the program.

One more reason is even if you have written the main function but if you didnot save the .cpp file and try to compile it will give the same error.So make sure you have successfully saved the .cpp file and then compile and run your code.

Hope this will help since I have faced similar issue and I spent around hours to figure it out , Thanks