man3/siginterrupt.3

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