IEEE/The Open Group
This manual page is part of the POSIX Programmer’s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
posix_spawnattr_destroy, posix_spawnattr_init — destroy and initialize spawn attributes object (ADVANCED REALTIME)
int posix_spawnattr_destroy(posix_spawnattr_t *attr); int posix_spawnattr_init(posix_spawnattr_t *attr);
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_spawnattr_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. POSIX.1-2008 does not define comparison 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 POSIX.1-2008. Attributes not defined by POSIX.1-2008, 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.
Upon successful completion, posix_spawnattr_destroy() and posix_spawnattr_init() shall return zero; otherwise, an error number shall be returned to indicate the error.
The posix_spawnattr_init() function shall fail if:
The following sections are informative.
|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.|
These functions are part of the Spawn option and need not be provided on all implementations.
The original spawn interface proposed in POSIX.1-2008 defined the attributes that specify the inheritance of process attributes across a spawn operation as a structure. In order to be able to separate optional individual attributes under their appropriate options (that is, the spawn-schedparam and spawn-schedpolicy attributes depending 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.
posix_spawn(), posix_spawnattr_getsigdefault(), posix_spawnattr_getflags(), posix_spawnattr_getpgroup(), posix_spawnattr_getschedparam(), posix_spawnattr_getschedpolicy(), posix_spawnattr_getsigmask()
The Base Definitions volume of POSIX.1-2008, <spawn.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
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