Issues with creating a mac DYLIB for system() function

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C

OS-X

I am trying to write a DYLIB, (in Code::Blocks), which is to be called from a Mac application, that simply calls the standard C system() function, while giving the option of whether to wait for finishing, in the second argument, (1 or 0).

#import <pthread.h>
#import <stdlib.h>
#include <unistd.h>

extern "C"
{
    char *tfname;

    void *system_async(void *arg)
    {
        system(tfname);

        return NULL;
    }

    double ExecuteShell(char *fname,double wait)
    {
        pthread_t tID;
        tfname = fname;

        if (wait>=1)
        {
            system(fname);
        }
        else
        {
            pthread_create(&tID,NULL,&system_async,NULL);
            usleep(5000);
        }

        return 0;
    }
}

Now when calling the DYLIB, (I can't remember the compiler I used, either GCC or LLVM), I use this code within GameMaker Studio:

ExecuteShell('open /Applications/Calculator.app',0);

However, calculator does not run. Trying to change the second argument to 1, and I get the same result. Calculator does not run. No errors. It seems to be ignoring my code all together, so I was wondering if there was something wrong with how I wrote my DYLIB.

I look at this question someone else had: link.

string command = "open " + filePath;
system(command.c_str());

I see they used .c_str(). Should I be using .c_str()? Is that the problem? The code I use right now is system(fname);. Should I change that to system(fname.c_str());? Is it OK that I'm using the type char * for the argument fname? Or because I'm using that type, do I have to cast/convert it to the type string?

I'm using someone else's Mac to port this small project of mine to work on Mac, anyway I'm trying to get help on here, before trying to build it again, because I'm trying to minimize how much I'm asking to use my friend's Mac computer. The hope is, the next build I do, with very little tweak, will finally work and run calculator.

Thanks in advance!

What I have tried:

#import <pthread.h>
#import <stdlib.h>
#include <unistd.h>

extern "C"
{
    char *tfname;

    void *system_async(void *arg)
    {
        system(tfname);

        return NULL;
    }

    double ExecuteShell(char *fname,double wait)
    {
        pthread_t tID;
        tfname = fname;

        if (wait>=1)
        {
            system(fname);
        }
        else
        {
            pthread_create(&tID,NULL,&system_async,NULL);
            usleep(5000);
        }

        return 0;
    }
}