HP-UX Reference (11i v1 05/09) - 2 System Calls (vol 5)

sigstack(2) sigstack(2)

HP-UX EXTENSIONS - TO BE OBSOLETED

SYNOPSIS

int sigstack(

const struct sigstack *ss,

struct sigstack *oss

);

DESCRIPTION

The correct use of sigstack() is hardware dependent, and therefore is not portable between different

HP-UX implementations.

sigspace() is portable between different HP-UX implementations and should

be used when the application does not need to know where the signal stack is located (see sigspace(2)).

sigstack() is provided for compatibility with other systems that provide this functionality. Users

should note that there is no guarantee that functionality similar to this is even possible on some architec-

tures.

The value stored in the ss_onstack member tells whether the process is currently using a signal stack, and

if so, the value stored in the ss_sp member is the current stack pointer for the stack in use.

ERRORS

[EFAULT] Either of ss or oss is not a null pointer and points outside the allocated address

space of the process. The reliable detection of this error is implementation

dependent.

WARNINGS

Do not use

sigstack() in conjunction with sigspace() .

Methods for calculating the required stack size are not well developed.

Leaving the context of a service routine abnormally, such as by longjmp() (see setjmp(3C)), might

remove the guarantee that the ordinary execution of the program does not extend into the guaranteed

space. It might also cause the program to lose forever its ability to automatically increase the stack size,

causing the program to be limited to the guaranteed space.

Stack addresses grow from low addresses to high addresses; therefore the signal stack address provided to

sigstack(2) should point to the beginning of the space to be used for the signal stack. This address should

be aligned to an eight-byte boundary.

Obsolescent Interfaces

sigstack() is to be obsoleted at a future date.

AUTHOR

sigstack() was developed by HP and the University of California, Berkeley.