projects / unix-history / blame
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1 | .\" Copyright (c) 1985 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement | |
| 3 | .\" specifies the terms and conditions for redistribution. | |
| 4 | .\" | |
| eff6446c | 5 | .\" @(#)sigreturn.2 6.2 (Berkeley) %G% |
| 6decfcd4 KM |
6 | .\" |
| 7 | .TH SIGRETURN 2 "" | |
| 8 | .UC 6 | |
| 9 | .SH NAME | |
| 10 | sigreturn \- return from signal | |
| 11 | .SH SYNOPSIS | |
| 12 | .nf | |
| 13 | .B #include <signal.h> | |
| 14 | .PP | |
| 15 | .B struct sigcontext { | |
| 16 | .B int sc_onstack; | |
| 17 | .B int sc_mask; | |
| 18 | .B int sc_sp; | |
| 19 | .B int sc_fp; | |
| 20 | .B int sc_ap; | |
| 21 | .B int sc_pc; | |
| 22 | .B int sc_ps; | |
| 23 | .B }; | |
| 24 | .PP | |
| 25 | .B sigreturn(scp); | |
| 26 | .B struct sigcontext *scp; | |
| 27 | .SH DESCRIPTION | |
| 28 | .I Sigreturn | |
| 29 | allows users to atomically unmask, switch stacks, | |
| 30 | and return from a signal context. | |
| 31 | The processes signal mask and stack status are | |
| 32 | restored from the context. | |
| 33 | The system call does not return; | |
| 34 | the users stack pointer, frame pointer, argument pointer, | |
| 35 | and processor status longword are restored from the context. | |
| 36 | Execution resumes at the specified pc. | |
| 37 | This system call is used by the trampoline code, and | |
| 38 | .IR longjmp (3) | |
| 39 | when returning from a signal to the previously executing program. | |
| 40 | .SH NOTES | |
| 41 | This system call is not available in 4.2BSD, | |
| 42 | hence it should not be used if backward compatibility is needed. | |
| 43 | .SH "RETURN VALUE | |
| 44 | If successful, the system call does not return. | |
| 45 | Otherwise, a value of \-1 is returned and | |
| 46 | .I errno | |
| 47 | is set to indicate the error. | |
| 48 | .SH ERRORS | |
| 49 | .I Sigreturn | |
| 50 | will fail and the process context will remain unchanged | |
| 51 | if one of the following occurs. | |
| 52 | .TP 15 | |
| 53 | [EFAULT] | |
| 54 | .I Scp | |
| eff6446c | 55 | points to memory that is not a valid part of the process |
| 6decfcd4 KM |
56 | address space. |
| 57 | .TP | |
| 58 | [EINVAL] | |
| 59 | The process status longword is invalid or would improperly | |
| 60 | raise the privilege level of the process. | |
| 61 | .SH "SEE ALSO" | |
| 62 | sigvec(2), setjmp(3) |