Adding upstream version 6.05.01.upstream/6.05.01

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 823 insertions, 0 deletions

diff --git a/man3/posix_spawn.3 b/man3/posix_spawn.3
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+.\" Copyright (c) 2009 Bill O. Gallmeister (bgallmeister@gmail.com)
+.\" and Copyright 2010 Michael Kerrisk <mtk.manpages@gmail.com>
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.\" References consulted:
+.\"     Linux glibc source code
+.\"     POSIX 1003.1-2004 documentation
+.\"     (http://www.opengroup.org/onlinepubs/009695399)
+.\"
+.TH posix_spawn 3 2023-05-03 "Linux man-pages 6.05.01"
+.SH NAME
+posix_spawn, posix_spawnp \- spawn a process
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B #include <spawn.h>
+.PP
+.BI "int posix_spawn(pid_t *restrict " pid ", const char *restrict " path ,
+.BI "                const posix_spawn_file_actions_t *restrict " file_actions ,
+.BI "                const posix_spawnattr_t *restrict " attrp ,
+.BI "                char *const " argv [restrict],
+.BI "                char *const " envp [restrict]);
+.BI "int posix_spawnp(pid_t *restrict " pid ", const char *restrict " file ,
+.BI "                const posix_spawn_file_actions_t *restrict " file_actions ,
+.BI "                const posix_spawnattr_t *restrict " attrp ,
+.BI "                char *const " argv [restrict],
+.BI "                char *const " envp [restrict]);
+.fi
+.SH DESCRIPTION
+The
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+functions are used to create a new child process that executes
+a specified file.
+These functions were specified by POSIX to provide a standardized method
+of creating new processes on machines that lack the capability
+to support the
+.BR fork (2)
+system call.
+These machines are generally small, embedded systems lacking MMU support.
+.PP
+The
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+functions provide the functionality of a combined
+.BR fork (2)
+and
+.BR exec (3),
+with some optional housekeeping steps in the child process before the
+.BR exec (3).
+These functions are not meant to replace the
+.BR fork (2)
+and
+.BR execve (2)
+system calls.
+In fact, they provide only a subset of the functionality
+that can be achieved by using the system calls.
+.PP
+The only difference between
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+is the manner in which they specify the file to be executed by
+the child process.
+With
+.BR posix_spawn (),
+the executable file is specified as a pathname
+(which can be absolute or relative).
+With
+.BR posix_spawnp (),
+the executable file is specified as a simple filename;
+the system searches for this file in the list of directories specified by
+.B PATH
+(in the same way as for
+.BR execvp (3)).
+For the remainder of this page, the discussion is phrased in terms of
+.BR posix_spawn (),
+with the understanding that
+.BR posix_spawnp ()
+differs only on the point just described.
+.PP
+The remaining arguments to these two functions are as follows:
+.TP
+.I pid
+points to a buffer that is used to return the process ID
+of the new child process.
+.TP
+.I file_actions
+points to a
+.I "spawn file actions object"
+that specifies file-related actions to be performed in the child
+between the
+.BR fork (2)
+and
+.BR exec (3)
+steps.
+This object is initialized and populated before the
+.BR posix_spawn ()
+call using
+.BR posix_spawn_file_actions_init (3)
+and the
+.BR posix_spawn_file_actions_* ()
+functions.
+.TP
+.I attrp
+points to an
+.I attributes objects
+that specifies various attributes of the created child process.
+This object is initialized and populated before the
+.BR posix_spawn ()
+call using
+.BR posix_spawnattr_init (3)
+and the
+.BR posix_spawnattr_* ()
+functions.
+.TP
+.I argv
+.TQ
+.I envp
+specify the argument list and environment for the program
+that is executed in the child process, as for
+.BR execve (2).
+.PP
+Below, the functions are described in terms of a three-step process: the
+.BR fork ()
+step, the
+.RB pre- exec ()
+step (executed in the child),
+and the
+.BR exec ()
+step (executed in the child).
+.SS fork() step
+Since glibc 2.24, the
+.BR posix_spawn ()
+function commences by calling
+.BR clone (2)
+with
+.B CLONE_VM
+and
+.B CLONE_VFORK
+flags.
+Older implementations use
+.BR fork (2),
+or possibly
+.BR vfork (2)
+(see below).
+.PP
+The PID of the new child process is placed in
+.IR *pid .
+The
+.BR posix_spawn ()
+function then returns control to the parent process.
+.PP
+Subsequently, the parent can use one of the system calls described in
+.BR wait (2)
+to check the status of the child process.
+If the child fails in any of the housekeeping steps described below,
+or fails to execute the desired file,
+it exits with a status of 127.
+.PP
+Before glibc 2.24, the child process is created using
+.BR vfork (2)
+instead of
+.BR fork (2)
+when either of the following is true:
+.IP \[bu] 3
+the
+.I spawn-flags
+element of the attributes object pointed to by
+.I attrp
+contains the GNU-specific flag
+.BR POSIX_SPAWN_USEVFORK ;
+or
+.IP \[bu]
+.I file_actions
+is NULL and the
+.I spawn-flags
+element of the attributes object pointed to by
+.I attrp
+does \fInot\fP contain
+.BR POSIX_SPAWN_SETSIGMASK ,
+.BR POSIX_SPAWN_SETSIGDEF ,
+.BR POSIX_SPAWN_SETSCHEDPARAM ,
+.BR POSIX_SPAWN_SETSCHEDULER ,
+.BR POSIX_SPAWN_SETPGROUP ,
+or
+.BR POSIX_SPAWN_RESETIDS .
+.PP
+In other words,
+.BR vfork (2)
+is used if the caller requests it,
+or if there is no cleanup expected in the child before it
+.BR exec (3)s
+the requested file.
+.SS pre-exec() step: housekeeping
+In between the
+.B fork()
+and the
+.B exec()
+steps, a child process may need to perform a set of housekeeping actions.
+The
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+functions support a small, well-defined set of system tasks that the child
+process can accomplish before it executes the executable file.
+These operations are controlled by the attributes object pointed to by
+.I attrp
+and the file actions object pointed to by
+.IR file_actions .
+In the child, processing is done in the following sequence:
+.IP (1) 5
+Process attribute actions: signal mask, signal default handlers,
+scheduling algorithm and parameters,
+process group, and effective user and group IDs
+are changed as specified by the attributes object pointed to by
+.IR attrp .
+.IP (2)
+File actions, as specified in the
+.I file_actions
+argument,
+are performed in the order that they were specified using calls to the
+.BR posix_spawn_file_actions_add* ()
+functions.
+.IP (3)
+File descriptors with the
+.B FD_CLOEXEC
+flag set are closed.
+.PP
+All process attributes in the child,
+other than those affected by attributes specified in the
+object pointed to by
+.I attrp
+and the file actions in the object pointed to by
+.IR file_actions ,
+will be affected as though the child was created with
+.BR fork (2)
+and it executed the program with
+.BR execve (2).
+.PP
+The process attributes actions are defined by the attributes object
+pointed to by
+.IR attrp .
+The
+.I spawn-flags
+attribute (set using
+.BR posix_spawnattr_setflags (3))
+controls the general actions that occur,
+and other attributes in the object specify values
+to be used during those actions.
+.PP
+The effects of the flags that may be specified in
+.I spawn-flags
+are as follows:
+.TP
+.B POSIX_SPAWN_SETSIGMASK
+Set the signal mask to the signal set specified in the
+.I spawn-sigmask
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setsigmask (3))
+of the object pointed to by
+.IR attrp .
+If the
+.B POSIX_SPAWN_SETSIGMASK
+flag is not set, then the child inherits the parent's signal mask.
+.TP
+.B POSIX_SPAWN_SETSIGDEF
+Reset the disposition of all signals in the set specified in the
+.I spawn-sigdefault
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setsigdefault (3))
+of the object pointed to by
+.I attrp
+to the default.
+For the treatment of the dispositions of signals not specified in the
+.I spawn-sigdefault
+attribute, or the treatment when
+.B POSIX_SPAWN_SETSIGDEF
+is not specified, see
+.BR execve (2).
+.TP
+.B POSIX_SPAWN_SETSCHEDPARAM
+.\" (POSIX_PRIORITY_SCHEDULING only)
+If this flag is set, and the
+.B POSIX_SPAWN_SETSCHEDULER
+flag is not set, then set the scheduling parameters
+to the parameters specified in the
+.I spawn-schedparam
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setschedparam (3))
+of the object pointed to by
+.IR attrp .
+.TP
+.B POSIX_SPAWN_SETSCHEDULER
+Set the scheduling policy algorithm and parameters of the child,
+as follows:
+.RS
+.IP \[bu] 3
+The scheduling policy is set to the value specified in the
+.I spawn-schedpolicy
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setpolicy (3))
+of the object pointed to by
+.IR attrp .
+.IP \[bu]
+The scheduling parameters are set to the value specified in the
+.I spawn-schedparam
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setschedparam (3))
+of the object pointed to by
+.I attrp
+(but see BUGS).
+.PP
+If the
+.B POSIX_SPAWN_SETSCHEDPARAM
+and
+.B POSIX_SPAWN_SETSCHEDPOLICY
+flags are not specified,
+the child inherits the corresponding scheduling attributes from the parent.
+.RE
+.TP
+.B POSIX_SPAWN_RESETIDS
+If this flag is set,
+reset the effective UID and GID to the
+real UID and GID of the parent process.
+If this flag is not set,
+then the child retains the effective UID and GID of the parent.
+In either case, if the set-user-ID and set-group-ID permission
+bits are enabled on the executable file, their effect will override
+the setting of the effective UID and GID (se
+.BR execve (2)).
+.TP
+.B POSIX_SPAWN_SETPGROUP
+Set the process group to the value specified in the
+.I spawn-pgroup
+attribute
+.\" FIXME .
+.\" (see
+.\" .BR posix_spawnattr_setpgroup (3))
+of the object pointed to by
+.IR attrp .
+If the
+.I spawn-pgroup
+attribute has the value 0,
+the child's process group ID is made the same as its process ID.
+If the
+.B POSIX_SPAWN_SETPGROUP
+flag is not set, the child inherits the parent's process group ID.
+.TP
+.B POSIX_SPAWN_USEVFORK
+Since glibc 2.24, this flag has no effect.
+On older implementations, setting this flag forces the
+.B fork()
+step to use
+.BR vfork (2)
+instead of
+.BR fork (2).
+The
+.B _GNU_SOURCE
+feature test macro must be defined to obtain the definition of this constant.
+.TP
+.BR POSIX_SPAWN_SETSID " (since glibc 2.26)"
+If this flag is set,
+the child process shall create a new session and become the session leader.
+The child process shall also become the process group leader of the new process
+group in the session (see
+.BR setsid (2)).
+The
+.B _GNU_SOURCE
+feature test macro must be defined to obtain the definition of this constant.
+.\" This flag has been accepted in POSIX, see:
+.\" http://austingroupbugs.net/view.php?id=1044
+.\" and has been implemented since glibc 2.26
+.\" commit daeb1fa2e1b33323e719015f5f546988bd4cc73b
+.PP
+If
+.I attrp
+is NULL, then the default behaviors described above for each flag apply.
+.\" mtk: I think we probably don't want to say the following, since it
+.\"      could lead people to do the wrong thing
+.\" The POSIX standard tells you to call
+.\" this function to de-initialize the attributes object pointed to by
+.\" .I attrp
+.\" when you are done with it;
+.\" however, on Linux systems this operation is a no-op.
+.PP
+The
+.I file_actions
+argument specifies a sequence of file operations
+that are performed in the child process after
+the general processing described above, and before it performs the
+.BR exec (3).
+If
+.I file_actions
+is NULL, then no special action is taken, and standard
+.BR exec (3)
+semantics apply\[em]file descriptors open before the exec
+remain open in the new process,
+except those for which the
+.B FD_CLOEXEC
+flag has been set.
+File locks remain in place.
+.PP
+If
+.I file_actions
+is not NULL, then it contains an ordered set of requests to
+.BR open (2),
+.BR close (2),
+and
+.BR dup2 (2)
+files.
+These requests are added to the
+.I file_actions
+by
+.BR posix_spawn_file_actions_addopen (3),
+.BR posix_spawn_file_actions_addclose (3),
+and
+.BR posix_spawn_file_actions_adddup2 (3).
+The requested operations are performed in the order they were added to
+.IR file_actions .
+.\" FIXME . I think the following is best placed in the
+.\" posix_spawn_file_actions_adddup2(3) page, and a similar statement is
+.\" also needed in posix_spawn_file_actions_addclose(3)
+.\" Note that you can specify file descriptors in
+.\" .I posix_spawn_file_actions_adddup2 (3)
+.\" which would not be usable if you called
+.\" .BR dup2 (2)
+.\" at that time--i.e., file descriptors that are opened or
+.\" closed by the earlier operations
+.\" added to
+.\" .I file_actions .
+.PP
+If any of the housekeeping actions fails
+(due to bogus values being passed or other reasons why signal handling,
+process scheduling, process group ID functions,
+and file descriptor operations might fail),
+the child process exits with exit value 127.
+.SS exec() step
+Once the child has successfully forked and performed
+all requested pre-exec steps,
+the child runs the requested executable.
+.PP
+The child process takes its environment from the
+.I envp
+argument, which is interpreted as if it had been passed to
+.BR execve (2).
+The arguments to the created process come from the
+.I argv
+argument, which is processed as for
+.BR execve (2).
+.SH RETURN VALUE
+Upon successful completion,
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+place the PID of the child process in
+.IR pid ,
+and return 0.
+If there is an error during the
+.B fork()
+step,
+then no child is created,
+the contents of
+.I *pid
+are unspecified,
+and these functions return an error number as described below.
+.PP
+Even when these functions return a success status,
+the child process may still fail for a plethora of reasons related to its
+pre-\fBexec\fR() initialization.
+In addition, the
+.BR exec (3)
+may fail.
+In all of these cases, the child process will exit with the exit value of 127.
+.SH ERRORS
+The
+.BR posix_spawn ()
+and
+.BR posix_spawnp ()
+functions fail only in the case where the underlying
+.BR fork (2),
+.BR vfork (2),
+or
+.BR clone (2)
+call fails;  in these cases, these functions return an error number,
+which will be one of the errors described for
+.BR fork (2),
+.BR vfork (2),
+or
+.BR clone (2).
+.PP
+In addition, these functions fail if:
+.TP
+.B ENOSYS
+Function not supported on this system.
+.SH STANDARDS
+POSIX.1-2008.
+.SH HISTORY
+glibc 2.2.
+POSIX.1-2001.
+.\" FIXME . This piece belongs in spawnattr_setflags(3)
+.\" The
+.\" .B POSIX_SPAWN_USEVFORK
+.\" flag is a GNU extension; the
+.\" .B _GNU_SOURCE
+.\" feature test macro must be defined (before including any header files)
+.\" to obtain the definition of this constant.
+.SH NOTES
+The housekeeping activities in the child are controlled by
+the objects pointed to by
+.I attrp
+(for non-file actions) and
+.I file_actions
+In POSIX parlance, the
+.I posix_spawnattr_t
+and
+.I posix_spawn_file_actions_t
+data types are referred to as objects,
+and their elements are not specified by name.
+Portable programs should initialize these objects using
+only the POSIX-specified functions.
+(In other words,
+although these objects may be implemented as structures containing fields,
+portable programs must avoid dependence on such implementation details.)
+.PP
+According to POSIX, it is unspecified whether fork handlers established with
+.BR pthread_atfork (3)
+are called when
+.BR posix_spawn ()
+is invoked.
+Since glibc 2.24, the fork handlers are not executed in any case.
+.\" Tested on glibc 2.12
+On older implementations,
+fork handlers are called only if the child is created using
+.BR fork (2).
+.PP
+There is no "posix_fspawn" function (i.e., a function that is to
+.BR posix_spawn ()
+as
+.BR fexecve (3)
+is to
+.BR execve (2)).
+However, this functionality can be obtained by specifying the
+.I path
+argument as one of the files in the caller's
+.I /proc/self/fd
+directory.
+.SH BUGS
+POSIX.1 says that when
+.B POSIX_SPAWN_SETSCHEDULER
+is specified in
+.IR spawn-flags ,
+then the
+.B POSIX_SPAWN_SETSCHEDPARAM
+(if present) is ignored.
+However, before glibc 2.14, calls to
+.BR posix_spawn ()
+failed with an error if
+.\" http://sourceware.org/bugzilla/show_bug.cgi?id=12052
+.B POSIX_SPAWN_SETSCHEDULER
+was specified without also specifying
+.BR POSIX_SPAWN_SETSCHEDPARAM .
+.SH EXAMPLES
+The program below demonstrates the use of various functions in the
+POSIX spawn API.
+The program accepts command-line attributes that can be used
+to create file actions and attributes objects.
+The remaining command-line arguments are used as the executable name
+and command-line arguments of the program that is executed in the child.
+.PP
+In the first run, the
+.BR date (1)
+command is executed in the child, and the
+.BR posix_spawn ()
+call employs no file actions or attributes objects.
+.PP
+.in +4n
+.EX
+$ \fB./a.out date\fP
+PID of child: 7634
+Tue Feb  1 19:47:50 CEST 2011
+Child status: exited, status=0
+.EE
+.in
+.PP
+In the next run, the
+.I \-c
+command-line option is used to create a file actions object that closes
+standard output in the child.
+Consequently,
+.BR date (1)
+fails when trying to perform output and exits with a status of 1.
+.PP
+.in +4n
+.EX
+$ \fB./a.out \-c date\fP
+PID of child: 7636
+date: write error: Bad file descriptor
+Child status: exited, status=1
+.EE
+.in
+.PP
+In the next run, the
+.I \-s
+command-line option is used to create an attributes object that
+specifies that all (blockable) signals in the child should be blocked.
+Consequently, trying to kill child with the default signal sent by
+.BR kill (1)
+(i.e.,
+.BR SIGTERM )
+fails, because that signal is blocked.
+Therefore, to kill the child,
+.B SIGKILL
+is necessary
+.RB ( SIGKILL
+can't be blocked).
+.PP
+.in +4n
+.EX
+$ \fB./a.out \-s sleep 60 &\fP
+[1] 7637
+$ PID of child: 7638
+.PP
+$ \fBkill 7638\fP
+$ \fBkill \-KILL 7638\fP
+$ Child status: killed by signal 9
+[1]+  Done                    ./a.out \-s sleep 60
+.EE
+.in
+.PP
+When we try to execute a nonexistent command in the child, the
+.BR exec (3)
+fails and the child exits with a status of 127.
+.PP
+.in +4n
+.EX
+$ \fB./a.out xxxxx
+PID of child: 10190
+Child status: exited, status=127
+.EE
+.in
+.SS Program source
+\&
+.\" SRC BEGIN (posix_spawn.c)
+.EX
+#include <errno.h>
+#include <spawn.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wait.h>
+\&
+#define errExit(msg)    do { perror(msg); \e
+                             exit(EXIT_FAILURE); } while (0)
+\&
+#define errExitEN(en, msg) \e
+                        do { errno = en; perror(msg); \e
+                             exit(EXIT_FAILURE); } while (0)
+\&
+char **environ;
+\&
+int
+main(int argc, char *argv[])
+{
+    pid_t child_pid;
+    int s, opt, status;
+    sigset_t mask;
+    posix_spawnattr_t attr;
+    posix_spawnattr_t *attrp;
+    posix_spawn_file_actions_t file_actions;
+    posix_spawn_file_actions_t *file_actionsp;
+\&
+    /* Parse command\-line options, which can be used to specify an
+       attributes object and file actions object for the child. */
+\&
+    attrp = NULL;
+    file_actionsp = NULL;
+\&
+    while ((opt = getopt(argc, argv, "sc")) != \-1) {
+        switch (opt) {
+        case \[aq]c\[aq]:       /* \-c: close standard output in child */
+\&
+            /* Create a file actions object and add a "close"
+               action to it. */
+\&
+            s = posix_spawn_file_actions_init(&file_actions);
+            if (s != 0)
+                errExitEN(s, "posix_spawn_file_actions_init");
+\&
+            s = posix_spawn_file_actions_addclose(&file_actions,
+                                                  STDOUT_FILENO);
+            if (s != 0)
+                errExitEN(s, "posix_spawn_file_actions_addclose");
+\&
+            file_actionsp = &file_actions;
+            break;
+\&
+        case \[aq]s\[aq]:       /* \-s: block all signals in child */
+\&
+            /* Create an attributes object and add a "set signal mask"
+               action to it. */
+\&
+            s = posix_spawnattr_init(&attr);
+            if (s != 0)
+                errExitEN(s, "posix_spawnattr_init");
+            s = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK);
+            if (s != 0)
+                errExitEN(s, "posix_spawnattr_setflags");
+\&
+            sigfillset(&mask);
+            s = posix_spawnattr_setsigmask(&attr, &mask);
+            if (s != 0)
+                errExitEN(s, "posix_spawnattr_setsigmask");
+\&
+            attrp = &attr;
+            break;
+        }
+    }
+\&
+    /* Spawn the child. The name of the program to execute and the
+       command\-line arguments are taken from the command\-line arguments
+       of this program. The environment of the program execed in the
+       child is made the same as the parent\[aq]s environment. */
+\&
+    s = posix_spawnp(&child_pid, argv[optind], file_actionsp, attrp,
+                     &argv[optind], environ);
+    if (s != 0)
+        errExitEN(s, "posix_spawn");
+\&
+    /* Destroy any objects that we created earlier. */
+\&
+    if (attrp != NULL) {
+        s = posix_spawnattr_destroy(attrp);
+        if (s != 0)
+            errExitEN(s, "posix_spawnattr_destroy");
+    }
+\&
+    if (file_actionsp != NULL) {
+        s = posix_spawn_file_actions_destroy(file_actionsp);
+        if (s != 0)
+            errExitEN(s, "posix_spawn_file_actions_destroy");
+    }
+\&
+    printf("PID of child: %jd\en", (intmax_t) child_pid);
+\&
+    /* Monitor status of the child until it terminates. */
+\&
+    do {
+        s = waitpid(child_pid, &status, WUNTRACED | WCONTINUED);
+        if (s == \-1)
+            errExit("waitpid");
+\&
+        printf("Child status: ");
+        if (WIFEXITED(status)) {
+            printf("exited, status=%d\en", WEXITSTATUS(status));
+        } else if (WIFSIGNALED(status)) {
+            printf("killed by signal %d\en", WTERMSIG(status));
+        } else if (WIFSTOPPED(status)) {
+            printf("stopped by signal %d\en", WSTOPSIG(status));
+        } else if (WIFCONTINUED(status)) {
+            printf("continued\en");
+        }
+    } while (!WIFEXITED(status) && !WIFSIGNALED(status));
+\&
+    exit(EXIT_SUCCESS);
+}
+.EE
+.\" SRC END
+.SH SEE ALSO
+.nh \" Disable hyphenation
+.ad l
+.BR close (2),
+.BR dup2 (2),
+.BR execl (2),
+.BR execlp (2),
+.BR fork (2),
+.BR open (2),
+.BR sched_setparam (2),
+.BR sched_setscheduler (2),
+.BR setpgid (2),
+.BR setuid (2),
+.BR sigaction (2),
+.BR sigprocmask (2),
+.BR posix_spawn_file_actions_addclose (3),
+.BR posix_spawn_file_actions_adddup2 (3),
+.BR posix_spawn_file_actions_addopen (3),
+.BR posix_spawn_file_actions_destroy (3),
+.BR posix_spawn_file_actions_init (3),
+.BR posix_spawnattr_destroy (3),
+.BR posix_spawnattr_getflags (3),
+.BR posix_spawnattr_getpgroup (3),
+.BR posix_spawnattr_getschedparam (3),
+.BR posix_spawnattr_getschedpolicy (3),
+.BR posix_spawnattr_getsigdefault (3),
+.BR posix_spawnattr_getsigmask (3),
+.BR posix_spawnattr_init (3),
+.BR posix_spawnattr_setflags (3),
+.BR posix_spawnattr_setpgroup (3),
+.BR posix_spawnattr_setschedparam (3),
+.BR posix_spawnattr_setschedpolicy (3),
+.BR posix_spawnattr_setsigdefault (3),
+.BR posix_spawnattr_setsigmask (3),
+.BR pthread_atfork (3),
+.IR <spawn.h> ,
+Base Definitions volume of POSIX.1-2001,
+.I http://www.opengroup.org/unix/online.html