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924dca35 | 1 | .\" Copyright (c) 2005 Michael Kerrisk |
c13182ef | 2 | .\" based on earlier work by faith@cs.unc.edu and |
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3 | .\" Mike Battersby <mib@deakin.edu.au> |
4 | .\" | |
93015253 | 5 | .\" %%%LICENSE_START(VERBATIM) |
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6 | .\" Permission is granted to make and distribute verbatim copies of this |
7 | .\" manual provided the copyright notice and this permission notice are | |
8 | .\" preserved on all copies. | |
9 | .\" | |
10 | .\" Permission is granted to copy and distribute modified versions of this | |
11 | .\" manual under the conditions for verbatim copying, provided that the | |
12 | .\" entire resulting derived work is distributed under the terms of a | |
13 | .\" permission notice identical to this one. | |
c13182ef | 14 | .\" |
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15 | .\" Since the Linux kernel and libraries are constantly changing, this |
16 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
17 | .\" responsibility for errors or omissions, or for damages resulting from | |
18 | .\" the use of the information contained herein. The author(s) may not | |
19 | .\" have taken the same level of care in the production of this manual, | |
20 | .\" which is licensed free of charge, as they might when working | |
21 | .\" professionally. | |
c13182ef | 22 | .\" |
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23 | .\" Formatted or processed versions of this manual, if unaccompanied by |
24 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 25 | .\" %%%LICENSE_END |
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26 | .\" |
27 | .\" 2005-09-15, mtk, Created new page by splitting off from sigaction.2 | |
28 | .\" | |
1e64c86b | 29 | .TH SIGSUSPEND 2 2015-03-29 "Linux" "Linux Programmer's Manual" |
924dca35 | 30 | .SH NAME |
1edfe5ac | 31 | sigsuspend, rt_sigsuspend \- wait for a signal |
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32 | .SH SYNOPSIS |
33 | .B #include <signal.h> | |
34 | .sp | |
35 | .BI "int sigsuspend(const sigset_t *" mask ); | |
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36 | .sp |
37 | .in -4n | |
38 | Feature Test Macro Requirements for glibc (see | |
39 | .BR feature_test_macros (7)): | |
40 | .in | |
41 | .sp | |
42 | .ad l | |
43 | .BR sigsuspend (): | |
44 | _POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE | |
45 | .ad b | |
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46 | .SH DESCRIPTION |
47 | .BR sigsuspend () | |
48 | temporarily replaces the signal mask of the calling process with the | |
c13182ef | 49 | mask given by |
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50 | .I mask |
51 | and then suspends the process until delivery of a signal whose | |
52 | action is to invoke a signal handler or to terminate a process. | |
53 | ||
54 | If the signal terminates the process, then | |
55 | .BR sigsuspend () | |
56 | does not return. | |
57 | If the signal is caught, then | |
58 | .BR sigsuspend () | |
59 | returns after the signal handler returns, | |
60 | and the signal mask is restored to the state before the call to | |
61 | .BR sigsuspend (). | |
62 | ||
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63 | It is not possible to block |
64 | .B SIGKILL | |
65 | or | |
66 | .BR SIGSTOP ; | |
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67 | specifying these signals in |
68 | .IR mask , | |
69 | has no effect on the process's signal mask. | |
47297adb | 70 | .SH RETURN VALUE |
924dca35 | 71 | .BR sigsuspend () |
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72 | always returns \-1, with |
73 | .I errno | |
48b58f28 | 74 | set to indicate the error (normally, |
d038a74a | 75 | .BR EINTR ). |
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76 | .SH ERRORS |
77 | .TP | |
78 | .B EFAULT | |
79 | .I mask | |
80 | points to memory which is not a valid part of the process address space. | |
81 | .TP | |
82 | .B EINTR | |
83 | The call was interrupted by a signal. | |
47297adb | 84 | .SH CONFORMING TO |
2dd578fd | 85 | POSIX.1-2001. |
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86 | .SH NOTES |
87 | .PP | |
c13182ef | 88 | Normally, |
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89 | .BR sigsuspend () |
90 | is used in conjunction with | |
0bfa087b | 91 | .BR sigprocmask (2) |
c13182ef | 92 | in order to prevent delivery of a signal during the execution of a |
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93 | critical code section. |
94 | The caller first blocks the signals with | |
0bfa087b | 95 | .BR sigprocmask (2). |
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96 | When the critical code has completed, the caller then waits for the |
97 | signals by calling | |
98 | .BR sigsuspend () | |
99 | with the signal mask that was returned by | |
0bfa087b | 100 | .BR sigprocmask (2) |
924dca35 | 101 | (in the |
0daa9e92 | 102 | .I oldset |
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103 | argument). |
104 | .PP | |
105 | See | |
106 | .BR sigsetops (3) | |
107 | for details on manipulating signal sets. | |
1edfe5ac | 108 | .\" |
0722a578 | 109 | .SS C library/kernel differences |
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110 | The original Linux system call was named |
111 | .BR sigsuspend (). | |
112 | However, with the addition of real-time signals in Linux 2.2, | |
113 | the fixed-size, 32-bit | |
114 | .IR sigset_t | |
115 | type supported by that system call was no longer fit for purpose. | |
116 | Consequently, a new system call, | |
117 | .BR rt_sigsuspend (), | |
118 | was added to support an enlarged | |
119 | .IR sigset_t | |
120 | type. | |
121 | The new system call takes a second argument, | |
122 | .IR "size_t sigsetsize" , | |
123 | which specifies the size in bytes of the signal set in | |
124 | .IR mask . | |
125 | This argument is currently required to have the value | |
126 | .IR sizeof(sigset_t) | |
127 | (or the error | |
128 | .B EINVAL | |
129 | results). | |
130 | The glibc | |
131 | .BR sigsuspend () | |
132 | wrapper function hides these details from us, transparently calling | |
133 | .BR rt_sigsuspend () | |
134 | when the kernel provides it. | |
135 | .\" | |
47297adb | 136 | .SH SEE ALSO |
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137 | .BR kill (2), |
138 | .BR pause (2), | |
139 | .BR sigaction (2), | |
140 | .BR signal (2), | |
141 | .BR sigprocmask (2), | |
142 | .BR sigwaitinfo (2), | |
143 | .BR sigsetops (3), | |
7c85aa6b | 144 | .BR sigwait (3), |
924dca35 | 145 | .BR signal (7) |