posix_spawn_file_actions_addclose.3   [plain text]

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.\"     @(#)posix_spawn_file_actions_addclose.3
.
.Dd November 2, 2010
.Dt POSIX_SPAWN_FILE_ACTIONS_ADDCLOSE 3
.Os "Mac OS X"
.Sh NAME
.Nm posix_spawn_file_actions_addclose
.Nm posix_spawn_file_actions_addopen
.Nd add open or close actions to a
.Em posix_spawn_file_actions_t
.Sh SYNOPSIS
.Fd #include <spawn.h>
.Ft int
.Fo posix_spawn_file_actions_addclose
.Fa "posix_spawn_file_actions_t *file_actions"
.Fa "int filedes"
.Fc
.Ft int
.Fo posix_spawn_file_actions_addopen
.Fa "posix_spawn_file_actions_t *restrict file_actions"
.Fa "int filedes"
.Fa "const char *restrict path"
.Fa "int oflag"
.Fa "mode_t mode"
.Fc
.Ft int
.Fo posix_spawn_file_actions_adddup2
.Fa "posix_spawn_file_actions_t *file_actions"
.Fa "int filedes"
.Fa "int newfiledes"
.Fc
.Ft int
.Fo posix_spawn_file_actions_addinherit_np
.Fa "posix_spawn_file_actions_t *file_actions"
.Fa "int filedes"
.Fc
.Sh DESCRIPTION
The
.Fn posix_spawn_file_actions_addclose
function adds a close operation to the list of operations associated with
the object referenced by
.Em file_actions ,
for subsequent use in a call to
.Xr posix_spawn 2
or 
.Xr posix_spawnp 2 .
The descriptor referred to by
.Em filedes
is closed as if
.Fn close
had been called on it prior to the new child process
starting execution.
.Pp
The
.Fn posix_spawn_file_actions_addopen
function adds an open operation to the list of operations associated with
the object referenced by
.Em file_actions ,
for subsequent use in a call to
.Xr posix_spawn 2
or 
.Xr posix_spawnp 2 .
The descriptor referred to by
.Em filedes
is opened using the
.Em path ,
.Em oflag ,
and
.Em mode
arguments as if
.Fn open
had been called on it prior to the new child process
starting execution.  The string
.Em path
is copied by the
.Fn posix_spawn_file_actions_addopen
function during this process, so storage need not be persistent in the
caller.
.Pp
The
.Fn posix_spawn_file_actions_adddup2
function adds a dup2 operation to the list of operations associated with
the object referenced by
.Em file_actions ,
for subsequent use in a call to
.Xr posix_spawn 2
or 
.Xr posix_spawnp 2 .
The descriptor referred to by
.Em newfiledes
is created as if
.Fn dup2
had been called on
.Em filedes
prior to the new child process starting execution.
.Pp
The
.Fn posix_spawn_file_actions_addinherit_np
function adds an abstract inheritance operation to the
list of operations associated with the object referenced by
.Em file_actions ,
for subsequent use in a call to
.Xr posix_spawn 2
or
.Xr posix_spawnp 2 .
The pre-existing descriptor referred to by
.Em filedes
is marked for inheritance into the new process image, and the
.Em FD_CLOEXEC
flag is cleared from the file descriptor in the new process image.
.Pp
Normally, for
.Xr posix_spawn 2
and
.Xr posix_spawnp 2 ,
all file descriptors are inherited from the parent process
into the spawned process, except for those explicitly
marked as close-on-exec.  However if the flag
.Em POSIX_SPAWN_CLOEXEC_DEFAULT
is set, then during the spawn operation, all pre-existing
file descriptors in the parent process are treated as if they
had been marked close-on-exec i.e. none of them are automatically
inherited.  See
.Xr posix_spawnattr_setflags 3 .
Only file descriptors explicitly manipulated via 
.Em file_actions
are made available in the spawned process. In that case,
.Fn posix_spawn_file_actions_addinherit_np
can be used to make specific pre-existing file
descriptors from the parent process be
available in the spawned process.
.Sh RETURN VALUES
On success, these functions return 0; on failure they return an error
number from
.In errno.h .
.Sh ERRORS
These functions may fail if:
.Bl -tag -width Er
.\" ==========
.It Bq Er EBADF
The value specified by
.Fa filedes
is negative or would cause the process to exceed the maximum number of
open files it is allowed.
.\" ==========
.It Bq Er EINVAL
The value of
.Fa file_actions
is invalid.
.\" ==========
.It Bq Er ENOMEM
Insufficient memory was available to add the new action to
.Fa file_actions .
.El
.Sh SEE ALSO
.Xr posix_spawn 2 ,
.Xr posix_spawnp 2 ,
.Xr posix_spawn_file_actions_init 3 ,
.Xr posix_spawn_file_actions_destroy 3 ,
.Xr posix_spawnattr_setflags 3 .
.Sh STANDARDS
.St -susv3 [SPN]
.Sh HISTORY
The
.Fn posix_spawn_file_actions_init
and
.Fn posix_spawn_file_actions_destroy
function calls appeared in
.St -susv3 [SPN] .