setpgid, setpgrp - Set the process group ID
#include <unistd.h>
int setpgid(
pid_t process_id,
pid_t process_group_id,
); pid_t setpgrp(
void );
Application developers may want to specify an #include
statement for <sys/types.h> before the one for <unistd.h>
if programs are being developed for multiple platforms.
The additional #include statement is not required on Tru64
UNIX systems or by ISO or XSH specifications, but may be
required on other vendors' systems that conform to these
standards.
The following alternate declaration for setpgrp() does not
conform to current standards and is supported only for
backward compatibility:
int setpgrp(
pid_t process_id,
pid_t process_group_id );
Interfaces documented on this reference page conform to
industry standards as follows:
setpgid(): XSH4.0, XSH4.2, XSH5.0
setpgrp(): SVID 3, XSH4.2, XSH5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Specifies the ID of the process whose process group ID is
to be changed. Specifies the new process group ID.
Use the setpgid() function to add a process to an existing
process group or to create a new process group within a
process's session. The setpgid() function does not change
the process group ID of a session leader.
The setpgid() function sets the process group ID of the
process identified by the process_id parameter. The process
group ID is set to the value specified in the process_group_id
parameter.
If the process_id parameter contains 0 (zero), the
setpgid() function sets the process group ID of the calling
process. The new value of the process group ID is the
one specified in the process_group_id parameter.
If the process_group_id parameter contains 0 (zero), the
setpgid() function sets the process group ID of the
specified process using the process group ID of the calling
process. The specified process is the one identified
by the process_id parameter.
The setpgid() function supports job control.
The setpgrp() function sets the process group ID of the
calling process to be equal to the process ID of the calling
process. If the function creates a new session, the
new session has no controlling terminal. This function
does not change the process group ID of a session leader.
[Tru64 UNIX] When compiled in compilation environments
that adhere to Revision 4.2 or higher revisions of the XSH
standard, calls to the setpgrp() function are internally
renamed by prepending _E to the function name. When you
are debugging a module that includes the setpgrp() function
prototype as defined in the _XOPEN_SOURCE_EXTENDED
compilation environment, use _Esetpgrp to refer to the
setpgrp() call. See standards(5) for further information.
[Tru64 UNIX] The backward-compatible version of the setpgrp()
function is supported for use outside of the System
V habitat or compilation environments that adhere to the
XSH standard. This version of setpgrp() is similar to the
setpgid() function in that you must specify the process ID
and process group ID as parameters in the call and errors
can be returned on these values. Like its industry-standard
counterpart, the backward-compatible version of setpgrp()
does not change the process group ID of a session
leader.
Upon successful completion, the setpgid() function returns
a value of 0 (zero). Otherwise, the function returns a
value of -1 and sets errno to indicate the error.
Upon successful completion, the setpgrp() function returns
the new process group ID.
[Tru64 UNIX] The backward-compatible version of setpgrp()
returns a value of 0 (zero) on successful completion. Otherwise,
the function returns a value of -1 and sets errno
to indicate the error.
The setpgid() function sets errno to the specified values
for the following conditions: The value of the process_id
parameter matches the process ID of a child process of the
calling process and the child process has successfully
executed one of the exec functions. The value of the process_group_id
parameter is less than or equal to 0 (zero),
or is not a valid process ID. The process indicated by
the process_id parameter is a session leader.
The value of the process_id parameter matches the
process ID of a child process of the calling process
and the child process is not in the same session
as the calling process.
The value of the process_group_id parameter is
valid but does not match the process ID of the process
indicated by the process_id parameter, and
there is no process with a process group ID that
matches the value of the process_group_id parameter
in the same session as the calling process. The
value of the process_id parameter does not match
the process ID of the calling process or of a child
process of the calling process.
No errors are defined for the industry-standard version of
the setpgrp() function.
[Tru64 UNIX] The backward-compatible version of setpgrp()
sets errno to the same values as setpgid().
Functions: exec(2), fork(2), getpid(2), getsid(2), kill(2)
Standards: standards(5)
Programmer's Guide
setpgid(2)
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