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.


       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 ALSO
       posix_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 .