POSIX_SPAWNATTR_DESTROY(P) POSIX Programmer's ManualPOSIX_SPAWNATTR_DESTROY(P)NAME
posix_spawnattr_destroy, posix_spawnattr_init - destroy and initialize
spawn attributes object (ADVANCED REALTIME)
SYNOPSIS
#include <spawn.h>
int posix_spawnattr_destroy(posix_spawnattr_t *attr);
int posix_spawnattr_init(posix_spawnattr_t *attr);
DESCRIPTION
The posix_spawnattr_destroy() function shall destroy a spawn attributes
object. A destroyed attr attributes object can be reinitialized using
posix_spawnattr_init(); the results of otherwise referencing the object
after it has been destroyed are undefined. An implementation may cause
posix_spawnattr_destroy() to set the object referenced by attr to an
invalid value.
The posix_spawnattr_init() function shall initialize a spawn attributes
object attr with the default value for all of the individual attributes
used by the implementation. Results are undefined if posix_spaw‐
nattr_init() is called specifying an already initialized attr
attributes object.
A spawn attributes object is of type posix_spawnattr_t (defined in
<spawn.h>) and is used to specify the inheritance of process attributes
across a spawn operation. IEEE Std 1003.1-2001 does not define compari‐
son or assignment operators for the type posix_spawnattr_t.
Each implementation shall document the individual attributes it uses
and their default values unless these values are defined by
IEEE Std 1003.1-2001. Attributes not defined by IEEE Std 1003.1-2001,
their default values, and the names of the associated functions to get
and set those attribute values are implementation-defined.
The resulting spawn attributes object (possibly modified by setting
individual attribute values), is used to modify the behavior of
posix_spawn() or posix_spawnp(). After a spawn attributes object has
been used to spawn a process by a call to a posix_spawn() or
posix_spawnp(), any function affecting the attributes object (including
destruction) shall not affect any process that has been spawned in this
way.
RETURN VALUE
Upon successful completion, posix_spawnattr_destroy() and posix_spaw‐
nattr_init() shall return zero; otherwise, an error number shall be
returned to indicate the error.
ERRORS
The posix_spawnattr_init() function shall fail if:
ENOMEM Insufficient memory exists to initialize the spawn attributes
object.
The posix_spawnattr_destroy() function may fail if:
EINVAL The value specified by attr is invalid.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
These functions are part of the Spawn option and need not be provided
on all implementations.
RATIONALE
The original spawn interface proposed in IEEE Std 1003.1-2001 defined
the attributes that specify the inheritance of process attributes
across a spawn operation as a structure. In order to be able to sepa‐
rate optional individual attributes under their appropriate options
(that is, the spawn-schedparam and spawn-schedpolicy attributes depend‐
ing upon the Process Scheduling option), and also for extensibility and
consistency with the newer POSIX interfaces, the attributes interface
has been changed to an opaque data type. This interface now consists of
the type posix_spawnattr_t, representing a spawn attributes object,
together with associated functions to initialize or destroy the
attributes object, and to set or get each individual attribute.
Although the new object-oriented interface is more verbose than the
original structure, it is simple to use, more extensible, and easy to
implement.
FUTURE DIRECTIONS
None.
SEE ALSOposix_spawn() , posix_spawnattr_getsigdefault() , posix_spawnattr_get‐
flags() , posix_spawnattr_getpgroup() , posix_spawnattr_getschedparam()
, posix_spawnattr_getschedpolicy() , posix_spawnattr_getsigmask() ,
posix_spawnattr_setsigdefault() , posix_spawnattr_setflags() ,
posix_spawnattr_setpgroup() , posix_spawnattr_setsigmask() ,
posix_spawnattr_setschedpolicy() , posix_spawnattr_setschedparam() ,
posix_spawnp() , the Base Definitions volume of IEEE Std 1003.1-2001,
<spawn.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 POSIX_SPAWNATTR_DESTROY(P)
