[C] Use fork to start application (pid+2)?!

[SpinningAround]

I start an application by using fork() then start the application from the child. Problem is that the pid of the application is not the pid return by fork() but pid+2. I'm not sure but using pid+2 don't seem reliable. Is there a better way to start an application, this is a test for Process.c in the 'real' program wont I know what application that will be started.

Process.c


#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>

#include "Process.h" //

int startProcess(const char *application){
int pid;
if((pid=fork())==-1){
fprintf(stderr,"Fork error. Exiting.\n");
exit(-1);
}

if(pid)
return pid;
else{
system(application);
exit(1);
}
}


Main.c



#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <signal.h>

#include "Process.h"
int main(void){
int pid = startProcess("gedit");
printf("%d\n",pid);
sleep(2);
kill(pid,9); // kill forked process
sleep(5);
kill(pid+2,9); //kill gedit
return 1;
}


shell output


9815
Killed

[StephenF]

Try using exec, not system. Using system will spawn a shell from which the application is launched.

[SpinningAround]

Try using exec, not system. Using system will spawn a shell from which the application is launched.

Thanks execlp solved it