projects / unix-history / blame
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1 | .\" Copyright (c) 1983 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| 95f51977 | 5 | .\" @(#)sigstack.2 6.2 (Berkeley) 6/30/85 |
| 39861f6c | 6 | .\" |
| 95f51977 | 7 | .TH SIGSTACK 2 "June 30, 1985" |
| 39861f6c KM |
8 | .UC 5 |
| 9 | .SH NAME | |
| 10 | sigstack \- set and/or get signal stack context | |
| 11 | .SH SYNOPSIS | |
| 12 | .nf | |
| 13 | .B #include <signal.h> | |
| 14 | .PP | |
| 15 | .B struct sigstack { | |
| 16 | .B caddr_t ss_sp; | |
| 17 | .B int ss_onstack; | |
| 18 | .B }; | |
| 19 | .PP | |
| 20 | .B sigstack(ss, oss); | |
| 21 | .B struct sigstack *ss, *oss; | |
| 22 | .SH DESCRIPTION | |
| 23 | .I Sigstack | |
| 24 | allows users to define an alternate stack on which signals | |
| 25 | are to be processed. If | |
| 26 | .I ss | |
| 27 | is non-zero, | |
| 28 | it specifies a | |
| 29 | .I "signal stack" | |
| 30 | on which to deliver signals | |
| 31 | and tells the system if the process is currently executing | |
| 32 | on that stack. When a signal's action indicates its handler | |
| 33 | should execute on the signal stack (specified with a | |
| 34 | .IR sigvec (2) | |
| 35 | call), the system checks to see | |
| 36 | if the process is currently executing on that stack. If the | |
| 37 | process is not currently executing on the signal stack, | |
| 38 | the system arranges a switch to the signal stack for the | |
| 39 | duration of the signal handler's execution. | |
| 40 | If | |
| 41 | .I oss | |
| 42 | is non-zero, the current signal stack state is returned. | |
| 43 | .SH NOTES | |
| 44 | Signal stacks are not ``grown'' automatically, as is | |
| 45 | done for the normal stack. If the stack overflows | |
| 46 | unpredictable results may occur. | |
| 47 | .SH "RETURN VALUE | |
| 48 | Upon successful completion, a value of 0 is returned. | |
| 49 | Otherwise, a value of \-1 is returned and | |
| 50 | .I errno | |
| 51 | is set to indicate the error. | |
| 52 | .SH ERRORS | |
| 53 | .I Sigstack | |
| 54 | will fail and the signal stack context will remain unchanged | |
| 55 | if one of the following occurs. | |
| 56 | .TP 15 | |
| 57 | [EFAULT] | |
| 58 | Either | |
| 59 | .I ss | |
| 60 | or | |
| 61 | .I oss | |
| eff6446c | 62 | points to memory that is not a valid part of the process |
| 39861f6c KM |
63 | address space. |
| 64 | .SH "SEE ALSO" | |
| 65 | sigvec(2), setjmp(3) |