C Tutorial: Playing with processes
Getting a process' process ID (PID)
Every process on the system has a unique process ID number, known as the pid. This is simply an integer. You can get the pid for a process via the getpid system call.
Example
This is a small program that simply prints its process ID number and exits.
/* getpid: print a process' process ID */
/* Paul Krzyzanowski */
#include <stdlib.h> /* needed to define exit() */
#include <unistd.h> /* needed to define getpid() */
#include <stdio.h> /* needed for printf() */
int
main(int argc, char **argv) {
printf("my process ID is %d\n", getpid());
exit(0);
}
Save this file by control-clicking or right clicking the download link and then saving it as getpid.c.
Compile this program via:
gcc -o getpid getpid.c
If you don't have gcc, You may need to substitute the gcc command with cc or another name of your compiler.
Run the program:
./getpid
