[C]undefined reference while compiling openCL program

I'm trying to compile something to try out openCl, but i'm having a few problems..

Here the code

prova.c

#include <stdio.h>
#include <CL/opencl.h>
#include "Utils\util.h"
#include <malloc.h>

int main(){
    cl_int error = 0;   // Used to handle error codes
    cl_int max_platforms = 1; // The maximum number of platforms
    cl_uint adviable_platforms = 0; //The adviable number of platforms
    cl_platform_id* platform;

    error = clGetPlatformIDs(0, NULL, &adviable_platforms);
    if(adviable_platforms == 0)
    {
        printf("No adviable platforms.\n");
        return -1;
    } else {
        platform = (cl_platform_id*)malloc(adviable_platforms * sizeof(cl_platform_id));
    }

    error = clGetPlatformIDs(adviable_platforms, platform, NULL);


    printf("clGetPlatformIDs: %s\n", clErrorString(error));
    return 0;
}

I'm compiling on win 7 64 with mingw32. The opencl headers are in the include directory of mingw while utils.h(inside the directory Utils inside the directory of prova.c) defines clErrorString(that simply convert the error into a more human readable string).

To compile i use

gcc -L\Utils prova.c

But i always get

C:\[stuff]\ccEjYQbj.o:prova.c:(.text+0x42): undefined reference to 'clGetPlatformIDs@12'
C:\[stuff]\ccEjYQbj.o:prova.c:(.text+0x8d): undefined reference to 'clGetPlatformIDs@12'
C:\[stuff]\ccEjYQbj.o:prova.c:(.text+0x9e): undefined reference to 'clErrorString'

I'm not so good with compilers, so i image i'm missing something, but i really don't know what..

EDIT: Sincerely, i tried every command come to my mind. using -L to include directories, -l to link to files, using ar..

This is the last "script" i tried

set PATH=%PATH%;C:\Python26;C:\MinGW\bin;C:\MinGW\lib

cd Utils
gcc -c util.c -l"C:\Program Files (x86)\AMD APP\lib\x86_64\libOpenCL.a" -o util.o
ar rcs libutil.a util.o

cd..
pause

gcc -c prova.c -l"Utils\libutil.a" -o prova.exe

pause

EDIT2:

@echo off
set PATH=%PATH%;C:\Python26;C:\MinGW\bin;C:\MinGW\lib

cd Utils
gcc -Wall -c util.c -L"C:\Program Files (x86)\AMD APP\lib\x86_64\" -o util.o
ar rcs libutil.a util.o

cd..
pause

gcc -Wall -c prova.c -L"C:\Program Files (x86)\AMD APP\lib\x86_64\" -l"Utils\libutil.a" -o prova.exe

pause

No errors, th开发者_开发知识库e only warning is max_platform is unused. Then i find util.o and libutil.a(size 5kb) in Utils and prova.o(size 1kb). If i try to run prova.o, it says that the file version is not compatible with the current windows version, check the system version (x86 or x64) and contact the software distributor

---

Try something like this:

set PATH=%PATH%;C:\Python26;C:\MinGW\bin;C:\MinGW\lib

cd Utils
gcc -W -Wall -c util.c -o util.o
ar rcs libutil.a util.o

cd..

gcc -W -Wall -c prova.c -o prova.o
gcc -o prova.exe prova.o Utils\libutil.a

# Using a standard library
gcc -o prog.exe myprog.o -lzip  # e.g. /usr/lib/libz.a

# Using a nonstandard library
gcc -o prog.exe myprog.o -lfoo -L/tmp/libfoo  # uses /tmp/libfoo/libfoo.a
gcc -o prog.exe myprog.o /tmp/libfoo/libfoo.a # same effect

In general:

• Compile single source files with -c:
  gcc -c myfile.c -o myfile.o.
  This creates object files.

• Link all the object files to an executable (or shared library):
  gcc -o prog.exe myfile.o yourstuff.o sha257.o

• You can combine object files into a static library, which you treat just like a single object file when linking:
  ar rcs libcoolstuff.a yourstuff.o sha257.o
gcc -o prog.exe myfile.o libcoolstuff.a
  Alternatively:
  gcc -o prog.exe myfile.o -lcoolstuff
  The latter syntax (automatic library linking with -l) requires either libcoolstuff.a or libcoolstuff.so to be findable in the library path (which you can amend with -L at linktime).