SETPGID(2) BSD System Calls Manual SETPGID(2)NAME
setpgid, setpgrp -- set process group
SYNOPSIS
#include <unistd.h>
int
setpgid(pid_t pid, pid_t pgid);
pid_t
setpgrp(void);
DESCRIPTION
setpgid() sets the process group of the specified process pid to the specified pgid. If pid is zero, then the call applies to the current
process.
If the invoker is not the super-user, then the affected process must have the same effective user-id as the invoker or be a descendant of the
invoking process.
RETURN VALUES
setpgid() returns 0 when the operation was successful. If the request failed, -1 is returned and the global variable errno indicates the
reason.
ERRORS
setpgid() will fail and the process group will not be altered if:
[EACCES] The value of the pid argument matches the process ID of a child process of the calling process, and the child process has
successfully executed one of the exec functions.
[EINVAL] The value of the pgid argument is less than 0 or is not a value supported by the implementation.
[EPERM] The process indicated by the pid argument is a session leader.
[EPERM] The effective user ID of the requested process is different from that of the caller and the process is not a descendant of
the calling process.
[EPERM] The value of the pgid argument is valid, but does not match the process ID of the process indicated by the pid argument
and there is no process with a process group ID that matches the value of the pgid argument in the same session as the
calling process.
[ESRCH] The value of the pid argument does not match the process ID of the calling process or of a child process of the calling
process.
LEGACY SYNOPSIS
#include <unistd.h>
int
setpgrp(pid_t pid, pid_t pgid);
The legacy setpgrp() function is a clone of the setpgid() function, retained for calling convention compatibility with historical versions of
BSD.
COMPATIBILITY
Use of the legacy version of the setpgrp() call will cause compiler diagnostics. Use setpgid() instead.
Use of private (and conflicting) prototypes for setpgrp() will cause compiler diagnostics. Delete the private prototypes and include
<unistd.h>.
SEE ALSO getpgrp(2), compat(5)STANDARDS
The setpgid() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution
Check Out this Related Man Page
SETPGID(2) Linux Programmer's Manual SETPGID(2)NAME
setpgid, getpgid, setpgrp, getpgrp - set/get process group
SYNOPSIS
#include <unistd.h>
int setpgid(pid_t pid, pid_t pgid);
pid_t getpgid(pid_t pid);
int setpgrp(void);
pid_t getpgrp(void);
DESCRIPTION
setpgid sets the process group ID of the process specified by pid to pgid. If pid is zero, the process ID of the current process is used.
If pgid is zero, the process ID of the process specified by pid is used. If setpgid is used to move a process from one process group to
another (as is done by some shells when creating pipelines), both process groups must be part of the same session. In this case, the pgid
specifies an existing process group to be joined and the session ID of that group must match the session ID of the joining process.
getpgid returns the process group ID of the process specified by pid. If pid is zero, the process ID of the current process is used.
In the Linux DLL 4.4.1 library, setpgrp simply calls setpgid(0,0).
getpgrp is equivalent to getpgid(0). Each process group is a member of a session and each process is a member of the session of which its
process group is a member.
Process groups are used for distribution of signals, and by terminals to arbitrate requests for their input: Processes that have the same
process group as the terminal are foreground and may read, while others will block with a signal if they attempt to read. These calls are
thus used by programs such as csh(1) to create process groups in implementing job control. The TIOCGPGRP and TIOCSPGRP calls described in
termios(3) are used to get/set the process group of the control terminal.
If a session has a controlling terminal, CLOCAL is not set and a hangup occurs, then the session leader is sent a SIGHUP. If the session
leader exits, the SIGHUP signal will be sent to each process in the foreground process group of the controlling terminal.
If the exit of the process causes a process group to become orphaned, and if any member of the newly-orphaned process group is stopped,
then a SIGHUP signal followed by a SIGCONT signal will be sent to each process in the newly-orphaned process group.
RETURN VALUE
On success, setpgid and setpgrp return zero. On error, -1 is returned, and errno is set appropriately.
getpgid returns a process group on success. On error, -1 is returned, and errno is set appropriately.
getpgrp always returns the current process group.
ERRORS
EINVAL pgid is less than 0 (setpgid, setpgrp).
EACCES An attempt was made to change the process group ID of one of the children of the calling process and the child had already performed
an execve (setpgid, setpgrp).
EPERM An attempt was made to move a process into a process group in a different session, or to change the process group ID of one of the
children of the calling process and the child was in a different session, or to change the process group ID of a session leader
(setpgid, setpgrp).
ESRCH pid does not match any process.
CONFORMING TO
The functions setpgid and getpgrp conform to POSIX.1. The function setpgrp is from BSD 4.2. The function getpgid conforms to SVr4.
NOTES
POSIX took setpgid from the BSD function setpgrp. Also SysV has a function with the same name, but it is identical to setsid(2).
To get the prototypes under glibc, define both _XOPEN_SOURCE and _XOPEN_SOURCE_EXTENDED, or use "#define _XOPEN_SOURCE n" for some integer
n larger than or equal to 500.
SEE ALSO getuid(2), setsid(2), tcsetpgrp(3), termios(3)Linux 1999-09-02 SETPGID(2)