Programming

# cat test.c
#include<unistd.h>
#include<stdio.h>

int main() {
        fprintf(stdout,"pid: %d\n",getpid());
        sleep(1000);
}
# cat test1.c
#include<stdio.h>
#include<sys/types.h>
#include<sys/wait.h>

int main() {
        int procid;
        fscanf(stdin,"%d",&procid);
        if((waitpid(procid,NULL,0))==-1) {
                perror("error in waitpid!!");
        }
}
# cc test.c -o test
# cc test1.c -o test1
# ./test &
[1] 5582
# pid: 5582

# ./test1
5582
error in waitpid!!: No child processes

/** OLD CODE **/
pid_t child=fork();

if (!child) { exit(run_child()); }

/** NEW CODE **/
pid_t surrogate=fork();

    if (!surrogate)
    {
        pid_t child=fork();
        if (!child) { exit(run_child()); }
        ... do stuff to monitor child and perform IPC until told to die ... 
        exit(0);
    }