GETSID(2)                 (2017-09-15)                  GETSID(2)

     NAME
          getsid - get session ID

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

          pid_t getsid(pid_t pid);

     Feature Test Macro Requirements for glibc (see
     feature_test_macros(7)):

          getsid():
              _XOPEN_SOURCE >= 500
                  || /* Since glibc 2.12: */
              _POSIX_C_SOURCE >= 200809L

     DESCRIPTION
          getsid(0) returns the session ID  of  the  calling  process.
          getsid()  returns the session ID of the process with process
          ID pid. If pid is 0, getsid() returns the session ID of  the
          calling process.

     RETURN VALUE
          On success, a session ID is returned.  On error,  (pid_t) -1
          will be returned, and errno is set appropriately.

     ERRORS
          EPERM
               A process with process ID pid exists, but it is not  in
               the same session as the calling process, and the imple-
               mentation considers this an error.

          ESRCH
               No process with process ID pid was found.

     VERSIONS
          This system call is available on Linux since version 2.0.

     CONFORMING TO
          POSIX.1-2001, POSIX.1-2008, SVr4.

     NOTES
          Linux does not return EPERM.

          See credentials(7) for a description of sessions and session
          IDs.

     SEE ALSO
          getpgid(2), setsid(2), credentials(7)

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     GETSID(2)                 (2017-09-15)                  GETSID(2)

     COLOPHON
          This page is part of release 5.10  of  the  Linux  man-pages
          project.   A  description  of the project, information about
          reporting bugs, and the latest version of this page, can  be
          found at https://www.kernel.org/doc/man-pages/.

     Page 2                        Linux             (printed 5/24/22)