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NAME

       pthread_attr_setstack, pthread_attr_getstack - set/get stack attributes
       in thread attributes object

SYNOPSIS

       #include <pthread.h>

       int pthread_attr_setstack(pthread_attr_t *attr,
                                 void *stackaddr, size_t stacksize);
       int pthread_attr_getstack(pthread_attr_t *attr,
                                 void **stackaddr, size_t *stacksize);

       Compile and link with -pthread.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       pthread_attr_getstack(), pthread_attr_setstack():
       _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600

DESCRIPTION

       The  pthread_attr_setstack()  function sets the stack address and stack
       size attributes of the thread attributes object referred to by attr  to
       the  values  specified in stackaddr and stacksize, respectively.  These
       attributes specify the location and size of the stack  that  should  be
       used  by  a  thread  that is created using the thread attributes object
       attr.

       stackaddr should point to the lowest addressable byte of  a  buffer  of
       stacksize  bytes  that  was  allocated by the caller.  The pages of the
       allocated buffer should be both readable and writable.

       The pthread_attr_getstack() function  returns  the  stack  address  and
       stack  size  attributes  of the thread attributes object referred to by
       attr  in  the  buffers  pointed  to   by   stackaddr   and   stacksize,
       respectively.

RETURN VALUE

       On  success,  these functions return 0; on error, they return a nonzero
       error number.

ERRORS

       pthread_attr_setstack() can fail with the following error:

       EINVAL stacksize is less than PTHREAD_STACK_MIN (16384) bytes.  On some
              systems,   this   error   may   also   occur   if  stackaddr  or
              stackaddr + stacksize is not suitably aligned.

       POSIX.1-2001 also documents an EACCES error if the stack area described
       by  stackaddr  and  stacksize  is not both readable and writable by the
       caller.

VERSIONS

       These functions are provided by glibc since version 2.2.

CONFORMING TO

       POSIX.1-2001.

NOTES

       These functions are provided for applications that must ensure  that  a
       thread’s   stack   is  placed  in  a  particular  location.   For  most
       applications, this is not necessary, and the  use  of  these  functions
       should be avoided.  (Use pthread_attr_setstacksize(3) if an application
       simply requires a stack size other than the default.)

       When an application employs pthread_attr_setstack(), it takes over  the
       responsibility  of allocating the stack.  Any guard size value that was
       set  using  pthread_attr_setguardsize(3)   is   ignored.    If   deemed
       necessary,  it  is the application’s responsibility to allocate a guard
       area (one or more pages  protected  against  reading  and  writing)  to
       handle the possibility of stack overflow.

       The address specified in stackaddr should be suitably aligned: for full
       portability, align  it  on  a  page  boundary  (sysconf(_SC_PAGESIZE)).
       posix_memalign(3)  may  be  useful for allocation.  Probably, stacksize
       should also be a multiple of the system page size.

       If attr is used to create multiple threads, then the caller must change
       the   stack  address  attribute  between  calls  to  pthread_create(3);
       otherwise, the threads will attempt to use the  same  memory  area  for
       their stacks, and chaos will ensue.

EXAMPLE

       See pthread_attr_init(3).

SEE ALSO

       mmap(2),    mprotect(2),    posix_memalign(3),    pthread_attr_init(3),
       pthread_attr_setguardsize(3),             pthread_attr_setstackaddr(3),
       pthread_attr_setstacksize(3), pthread_create(3), pthreads(7)

COLOPHON

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       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.