setsid - create session and set process group ID
Library Synopsis Description Return Values Errors See Also Standards
.In unistd.h pid_t setsid void
The setsid system call creates a new session. The calling process is the session leader of the new session, is the process group leader of a new process group and has no controlling terminal. The calling process is the only process in either the session or the process group.
Upon successful completion, the setsid system call returns the value of the process group ID of the new process group, which is the same as the process ID of the calling process. If an error occurs, setsid returns -1 and the global variable errno is set to indicate the error.
The setsid system call will fail if: