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  2002-08-25 "notGNU" "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(" signum );
  35 .sp
  36 .BI "sighandler_t ssignal(int " signum ", sighandler_t " action );
  37 .SH DESCRIPTION
  38 Don't use these functions under Linux.
  39 Due to a historical mistake, under Linux these functions are
  40 aliases for
  41 .BR raise ()
  42 and
  43 .BR signal (),
  44 respectively.
  45 .LP
  46 Elsewhere, on System V-like systems, these functions implement
  47 software signalling, entirely independent of the classical
  48 signal and kill functions.
  49 The function
  50 .BR ssignal ()
  51 defines the action to take when the software signal with
  52 number
  53 .I signum
  54 is raised using the function
  55 .BR gsignal (),
  56 and returns the previous such action or SIG_DFL.
  57 The function
  58 .BR gsignal ()
  59 does the following: if no action (or the action SIG_DFL) was
  60 specified for
  61 .IR signum ,
  62 then it does nothing and returns 0.
  63 If the action SIG_IGN was specified for
  64 .IR signum ,
  65 then it does nothing and returns 1.
  66 Otherwise, it resets the action to SIG_DFL and calls
  67 the action function with parameter
  68 .IR signum ,
  69 and returns the value returned by that function.
  70 The range of possible values
  71 .I signum
  72 varies (often 1-15 or 1-17).
  73 .SH "CONFORMING TO"
  74 These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64.
  75 They are called obsolete under most of these systems, and are
  76 broken under Linux libc and glibc.
  77 Some systems also have
  78 .BR gsignal_r ()
  79 and
  80 .BR ssignal_r ().
  81 .SH "SEE ALSO"
  82 .BR kill (2),
  83 .BR signal (2),
  84 .BR raise (3)