How to execute a program by fork and exec - c

Question

I have a binary file that contains a program with function written in C inside that looks like:
int main()
{
int a, b;
foo(a,b);
return 0;
}
And now I want to execute that program by using fork() and execve() in another program called "solver".
int main(int argc, char* argv[])
{
pid_t process;
process = fork();
if(process==0)
{
if(execve(argv[0], (char**)argv, NULL) == -1)
printf("The process could not be started\n");
}
return 0;
}
Is that a good way? Because it compiles, but I'm not sure whether the arguments of function inside "worker" program receive variables passed by command line to "solver" program

Answer 1

I believe you are trying to achieve something like that:
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/wait.h>
static char *sub_process_name = "./work";
int main(int argc, char *argv[])
{
pid_t process;
process = fork();
if (process < 0)
{
// fork() failed.
perror("fork");
return 2;
}
if (process == 0)
{
// sub-process
argv[0] = sub_process_name; // Just need to change where argv[0] points to.
execv(argv[0], argv);
perror("execv"); // Ne need to check execv() return value. If it returns, you know it failed.
return 2;
}
int status;
pid_t wait_result;
while ((wait_result = wait(&status)) != -1)
{
printf("Process %lu returned result: %d\n", (unsigned long) wait_result, status);
}
printf("All children have finished.\n");
return 0;
}
./work will be launched with the same arguments as your original program.