GETSID(2) Linux Programmer s Manual GETSID(2)
NAME getsid - get session ID
SYNOPSIS #include <unistd.h>
pid_t getsid(pid_t pid);
DESCRIPTION getsid(0) returns the session ID of the calling process. getsid(p) returns the session ID of the process with process ID p. (The session ID of a process is the process group ID of the session leader.) On error, (pid_t) -1 will be returned, and errno is set appropriately.
ERRORS EPERM A process with process ID p exists, but it is not in the same session as the current process, and the implementation considers this an error.
ESRCH No process with process ID p was found.
CONFORMING TO SVr4, POSIX.1-2001.
NOTES Linux does not return EPERM.
Linux has this system call since Linux 1.3.44. There is libc support since libc 5.2.19.
To get the prototype under glibc, define both _XOPEN_SOURCE and _XOPEN_SOURCE_EXTENDED, or use "#define _XOPEN_SOURCE n" for some inte- ger n larger than or equal to 500.
SEE ALSO getpgid(2), setsid(2), feature_test_macros(7)
Linux 2.5.0 2001-12-17 GETSID(2)