getustack(2)

NAME

     getustack, setustack - retrieve or  change  the  address  of
     per-LWP stack boundary information

SYNOPSIS

     #include <ucontext.h>

     int getustack(stack_t **spp);

     int setustack(stack_t *sp);

DESCRIPTION

     The getustack() function retrieves the  address  of  per-LWP
     stack  boundary  information.   The address is stored at the
     location pointed to by spp. If this  address  has  not  been
     defined using a previous call to setustack(), NULL is stored
     at the location pointed to by spp.

     The setustack() function changes the address of the  current
     thread's stack boundary information to the value of sp.

RETURN VALUES

     Upon successful completion, these functions return 0. Other-
     wise, -1 is returned and errno is set to indicate the error.

ERRORS

     These functions will fail if:

     EFAULT
           The spp or sp argument  does  not  refer  to  a  valid
           address.

USAGE

     Implementors of custom threading libraries should use setus-
     tack() to set the address of the stack bounds to in internal
     per-thread data structure.

ATTRIBUTES

     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |        ATTRIBUTE TYPE       |        ATTRIBUTE VALUE      |
    |_____________________________|_____________________________|
    | Interface Stability         |  Evolving                   |
    |_____________________________|_____________________________|
    | MT-Level                    |  Async-Signal-Safe          |
    |_____________________________|_____________________________|

SEE ALSO

     _stack_grow(3C),  stack_getbounds(3C),   stack_inbounds(3C),
     stack_setbounds(3C), stack_violation(3C), attributes(5)