getpid(), getppid() - get parent or calling process identification
#include <unistd.h>
pid_t getpid (void)
pid_t getppid (void)
The getpid(2) function returns the process ID of the calling process. The ID is guaranteed to be unique and is useful for constructing temporary file names.
The getppid(2) function returns the process ID of the parent of the calling process.
The getpid(2) and getppid(2) functions are always successful, and no return value is reserved to indicate an error.