How to get the return value of a program ran via calling a member of the exec family of functions?

by

Here is an example I wrote long time ago. Basically, after you fork a child process and you wait its exit status, you check the status using two Macros. WIFEXITED is used to check if the process exited normally, and WEXITSTATUS checks what the returned number is in case it returned normally:

#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>
int main()
{
    int number, statval;
    printf("%d: I'm the parent !\n", getpid());
    if(fork() == 0)
    {
        number = 10;
        printf("PID %d: exiting with number %d\n", getpid(), number);
        exit(number) ;
    }
    else
    {
        printf("PID %d: waiting for child\n", getpid());
        wait(&statval);
        if(WIFEXITED(statval))
            printf("Child's exit code %d\n", WEXITSTATUS(statval));
        else
            printf("Child did not terminate with exit\n");
    }
    return 0;
}

More Related Contents:

  1. Differences between fork and exec
  2. In C how do you redirect stdin/stdout/stderr to files when making an execvp() or similar call?
  3. Redirecting exec output to a buffer or file
  4. Using poll function with buffered streams
  5. Grabbing output from exec
  6. How do I execute a Shell built-in command with a C function?
  7. How to call execl() in C with the proper arguments?
  8. popen() alternative
  9. I do not understand how execlp() works in Linux
  10. how to correctly use fork, exec, wait
  11. Having trouble with fork(), pipe(), dup2() and exec() in C
  12. Difference between “system” and “exec” in Linux?
  13. Pipes, dup2 and exec()
  14. C – Retrieving a child’s exit status that is larger than 8 bits
  15. how to set close-on-exec by default
  16. How many times will “Hello World” be printed?
  17. c program to find average
  18. Improve INSERT-per-second performance of SQLite
  19. Difference between int and char in getchar/fgetc and putchar/fputc?
  20. How to read a line from the console in C?
  21. Can the size of pointers vary between data and function pointers?
  22. Why doesn’t C have unsigned floats?
  23. variably modified array at file scope in C
  24. When implementing an infinite loop, is there a difference in using while(1) vs for(;;) vs goto (in C)?
  25. executing default signal handler
  26. STM32 how to get last reset status
  27. pow() cast to integer, unexpected result
  28. How to get the size of a C function from inside a C program or with inline assembly?
  29. Iterating over same type struct members in C
  30. What’s the difference between “C system calls” and “C library routines”?

Leave a Comment