getpid(2)                                                         getpid(2)


   NAME
         getpid, getpgrp, getppid, getpgid - get process, process group, and
         parent process IDs

   SYNOPSIS
         #include <sys/types.h>
         #include <unistd.h>

         pid_t getpid(void);

         pid_t getpgrp(void);

         pid_t getppid(void);

         pid_t getpgid(pid_t pid);

   DESCRIPTION
         getpid returns the process ID of the calling process.

         getpgrp returns the process group ID of the calling process.

         getppid returns the parent process ID of the calling process.

         getpgid returns the process group ID of the process whose process ID
         is equal to pid, or the process group ID of the calling process, if
         pid is equal to zero.

         getpgid will fail if one or more of the following is true:

         EPERM          The process whose process ID is equal to pid is not in
                        the same session as the calling process, and the
                        implementation does not allow access to the process
                        group ID of that process from the calling process.

         ESRCH          There is no process with a process ID equal to pid.

   SEE ALSO
         exec(2), fork(2), getpid(2), getsid(2), intro(2), setpgid(2),
         setsid(2) setpgrp(2), signal(2).

   DIAGNOSTICS
         Upon successful completion, getpgid returns a process group ID.
         Otherwise, a value of (pid_t) -1 is returned and errno is set to
         indicate the error.









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