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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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       pages/.