man3/siginterrupt.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" References consulted:
   6 .\"     Linux libc source code
   7 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
   8 .\"     386BSD man pages
   9 .\" Modified Sun Jul 25 10:40:51 1993 by Rik Faith (faith@cs.unc.edu)
  10 .\" Modified Sun Apr 14 16:20:34 1996 by Andries Brouwer (aeb@cwi.nl)
  11 .TH SIGINTERRUPT 3 2022-09-09 "Linux man-pages (unreleased)"
  12 .SH NAME
  13 siginterrupt \- allow signals to interrupt system calls
  14 .SH LIBRARY
  15 Standard C library
  16 .RI ( libc ", " \-lc )
  17 .SH SYNOPSIS
  18 .nf
  19 .B #include <signal.h>
  20 .PP
  21 .BI "int siginterrupt(int " sig ", int " flag );
  22 .fi
  23 .PP
  24 .RS -4
  25 Feature Test Macro Requirements for glibc (see
  26 .BR feature_test_macros (7)):
  27 .RE
  28 .PP
  29 .BR siginterrupt ():
  30 .nf
  31     _XOPEN_SOURCE >= 500
  32 .\"    || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
  33         || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
  34         || /* Glibc <= 2.19: */ _BSD_SOURCE
  35 .fi
  36 .SH DESCRIPTION
  37 The
  38 .BR siginterrupt ()
  39 function changes the restart behavior when
  40 a system call is interrupted by the signal \fIsig\fP.
  41 If the \fIflag\fP
  42 argument is false (0), then system calls will be restarted if interrupted
  43 by the specified signal \fIsig\fP.
  44 This is the default behavior in Linux.
  45 .PP
  46 If the \fIflag\fP argument is true (1) and no data has been transferred,
  47 then a system call interrupted by the signal \fIsig\fP will return \-1
  48 and \fIerrno\fP will be set to
  49 .BR EINTR .
  50 .PP
  51 If the \fIflag\fP argument is true (1) and data transfer has started,
  52 then the system call will be interrupted and will return the actual
  53 amount of data transferred.
  54 .SH RETURN VALUE
  55 The
  56 .BR siginterrupt ()
  57 function returns 0 on success.
  58 It returns \-1 if the
  59 signal number
  60 .I sig
  61 is invalid, with
  62 .I errno
  63 set to indicate the error.
  64 .SH ERRORS
  65 .TP
  66 .B EINVAL
  67 The specified signal number is invalid.
  68 .SH ATTRIBUTES
  69 For an explanation of the terms used in this section, see
  70 .BR attributes (7).
  71 .ad l
  72 .nh
  73 .TS
  74 allbox;
  75 lb lb lbx
  76 l l l.
  77 Interface       Attribute       Value
  78 T{
  79 .BR siginterrupt ()
  80 T}      Thread safety   T{
  81 MT-Unsafe const:sigintr
  82 T}
  83 .TE
  84 .hy
  85 .ad
  86 .sp 1
  87 .SH STANDARDS
  88 4.3BSD, POSIX.1-2001.
  89 POSIX.1-2008 marks
  90 .BR siginterrupt ()
  91 as obsolete, recommending the use of
  92 .BR sigaction (2)
  93 with the
  94 .B SA_RESTART
  95 flag instead.
  96 .SH SEE ALSO
  97 .BR signal (2)