man3/gsignal.3

   1 .\" Copyright (C) 2002 Andries Brouwer <aeb@cwi.nl>
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  23 .\" This replaces an earlier man page written by Walter Harms
  24 .\" <walter.harms@informatik.uni-oldenburg.de>.
  25 .TH GSIGNAL 3  2007-07-26 "" "Linux Programmer's Manual"
  26 .SH NAME
  27 gsignal, ssignal \- software signal facility
  28 .SH SYNOPSIS
  29 .nf
  30 .B #include <signal.h>
  31 .sp
  32 .B typedef void (*sighandler_t)(int);
  33 .sp
  34 .BI "int gsignal(int" signum );
  35 .sp
  36 .BI "sighandler_t ssignal(int " signum ", sighandler_t " action );
  37 .fi
  38 .sp
  39 .in -4n
  40 Feature Test Macro Requirements for glibc (see
  41 .BR feature_test_macros (7)):
  42 .in
  43 .sp
  44 .BR gsignal (),
  45 .BR ssignal ():
  46 _SVID_SOURCE
  47 .SH DESCRIPTION
  48 Don't use these functions under Linux.
  49 Due to a historical mistake, under Linux these functions are
  50 aliases for
  51 .BR raise (3)
  52 and
  53 .BR signal (2),
  54 respectively.
  55 .LP
  56 Elsewhere, on System V-like systems, these functions implement
  57 software signaling, entirely independent of the classical
  58 signal and kill functions.
  59 The function
  60 .BR ssignal ()
  61 defines the action to take when the software signal with
  62 number
  63 .I signum
  64 is raised using the function
  65 .BR gsignal (),
  66 and returns the previous such action or
  67 .BR SIG_DFL .
  68 The function
  69 .BR gsignal ()
  70 does the following: if no action (or the action
  71 .BR SIG_DFL )
  72 was
  73 specified for
  74 .IR signum ,
  75 then it does nothing and returns 0.
  76 If the action
  77 .B SIG_IGN
  78 was specified for
  79 .IR signum ,
  80 then it does nothing and returns 1.
  81 Otherwise, it resets the action to
  82 .B SIG_DFL
  83 and calls
  84 the action function with parameter
  85 .IR signum ,
  86 and returns the value returned by that function.
  87 The range of possible values
  88 .I signum
  89 varies (often 1-15 or 1-17).
  90 .SH "CONFORMING TO"
  91 These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
  92 They are called obsolete under most of these systems, and are
  93 broken under Linux libc and glibc.
  94 Some systems also have
  95 .BR gsignal_r ()
  96 and
  97 .BR ssignal_r ().
  98 .SH "SEE ALSO"
  99 .BR kill (2),
 100 .BR signal (2),
 101 .BR raise (3)