Gradle undefined reference to `WinMain@16' error

Question

I am new to gradle and creating library, i am trying to create a lib and link it later on while creating executable. Specifically looking at gradle to do the build system. I am having below folder structure for the project,

NativeGradle(root folder)
    src
    build.gradle

(.h files are at)
NativeGradle\src\include -> includes (call.h and main.h)


source files (c files are at)

NativeGradle\src\atlas\call.c
NativeGradle\src\one\main.c

call.c:

#include "main.h"
#include "call.h"
void createSum()
{

    printf("Sum is %d\n", sumMe(5,4));

}


main.c

#include <stdio.h>
#include <windows.h>
#include <stdlib.h>
#include "call.h"

int sumMe(int a, int b)
{
    return (a+b);
}

int main()
{

    printf("Hellow world !!\n");
    createSum();
    return 0;
}

call.h

#include <stdio.h> 
#include "main.h"
void createSum(void);

main.h

#include <stdio.h>
int sumMe(int , int);

and below is the build.gradle am using

apply plugin: 'c'


model {  
    components {
     hello(NativeLibrarySpec) {
            sources {
                c {
                    source {
                        srcDirs "src/include"
                        include "call.h"
                        include "main.h"
                        srcDir "src/atlas"
                        include "*/call.c"
                    }

                }
            }
        }
    }

     components {
     out(NativeExecutableSpec) {
            sources {
                c {
                    source {
                        c.lib library: "hello" 
                        srcDirs "src/include"
                        include "call.h"
                        include "main.h"                      
                        srcDir "src/one"
                        include "*/main.c"
                    }

                }
            }
        }
    }


}

task wrapper(type: Wrapper) {
    gradleVersion = '2.3'
}

When i give gradle build command i get below error

c:/mingw/bin/../lib/gcc/mingw32/4.9.3/../../../libmingw32.a(main.o):(.text.startup+0xa7): undefined reference to `WinMain@16'
collect2.exe: error: ld returned 1 exit status

:linkOutExecutable FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':linkOutExecutable'.
> A build operation failed.
      Linker failed while linking out.exe.
  See the complete log at: file:///C:/PROS/Training/NativeGradle/build/tmp/linkOutExecutable/output.txt

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

linkOutExecutable content is

See file:///C:/PROS/Training/NativeGradle/build/tmp/linkOutExecutable/output.txt for all output for linkOutExecutable.
linking out.exe failed.
c:/mingw/bin/../lib/gcc/mingw32/4.9.3/../../../libmingw32.a(main.o):(.text.startup+0xa7): undefined reference to `WinMain@16'
collect2.exe: error: ld returned 1 exit status

Finished linkOutExecutable, see full log file:///C:/PROS/Training/NativeGradle/build/tmp/linkOutExecutable/output.txt.

Please help me to solve it Thank you

Answer 1

"WinMain" indicates that the compiler is set to link this as a Windows executable, rather than a console application.

If you want a console application with Mingw, you have to drop the option -mwindows .

If you want a Windows application, you have to provide an implementation-specific form of main , WinMain .