PR_SET_CHILD_SUBREAPER(2const) — Linux manual page

PR_SET_CHILD_SUBREAPER(2const)            PR_SET_CHILD_SUBREAPER(2const)

NAME

       PR_SET_CHILD_SUBREAPER - set/unset the "child subreaper"
       attribute of the calling process

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <linux/prctl.h>  /* Definition of PR_* constants */
       #include <sys/prctl.h>

       int prctl(PR_SET_CHILD_SUBREAPER, long set);

DESCRIPTION

       If set is nonzero, set the "child subreaper" attribute of the
       calling process; if set is zero, unset the attribute.

       A subreaper fulfills the role of init(1) for its descendant
       processes.  When a process becomes orphaned (i.e., its immediate
       parent terminates), then that process will be reparented to the
       nearest still living ancestor subreaper.  Subsequently, calls to
       getppid(2) in the orphaned process will now return the PID of the
       subreaper process, and when the orphan terminates, it is the
       subreaper process that will receive a SIGCHLD signal and will be
       able to wait(2) on the process to discover its termination
       status.

       The setting of the "child subreaper" attribute is not inherited
       by children created by fork(2) and clone(2).  The setting is
       preserved across execve(2).

       Establishing a subreaper process is useful in session management
       frameworks where a hierarchical group of processes is managed by
       a subreaper process that needs to be informed when one of the
       processes—for example, a double-forked daemon—terminates (perhaps
       so that it can restart that process).  Some init(1) frameworks
       (e.g., systemd(1)) employ a subreaper process for similar
       reasons.

RETURN VALUE

       On success, 0 is returned.  On error, -1 is returned, and errno
       is set to indicate the error.

STANDARDS

       Linux.

HISTORY

       Linux 3.4.

SEE ALSO

       prctl(2), PR_GET_CHILD_SUBREAPER(2const)

COLOPHON

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Linux man-pages 6.9.1          2024-06-02 PR_SET_CHILD_SUBREAPER(2const)

Pages that refer to this page: prctl(2), PR_GET_CHILD_SUBREAPER(2const), PR_SET_PDEATHSIG(2const)

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