Manpages - gsignal.3

gsignal, ssignal - software signal facility

  #include <signal.h>

  typedef void (*sighandler_t)(int);

  int gsignal(int signum);

  sighandler_t ssignal(int signum, sighandler_t action);

Feature Test Macro Requirements for glibc (see *feature_test_macros*(7)):

*gsignal*(), *ssignal*():

      Since glibc 2.19:
          _DEFAULT_SOURCE
      Glibc 2.19 and earlier:
          _SVID_SOURCE

Don’t use these functions under Linux. Due to a historical mistake, under Linux these functions are aliases for *raise*(3) and *signal*(2), respectively.

Elsewhere, on System V-like systems, these functions implement software signaling, entirely independent of the classical signal*(2) and *kill*(2) functions. The function *ssignal*() defines the action to take when the software signal with number signum is raised using the function *gsignal*(), and returns the previous such action or *SIG_DFL. The function gsignal*() does the following: if no action (or the action *SIG_DFL) was specified for signum, then it does nothing and returns 0. If the action SIG_IGN was specified for signum, then it does nothing and returns 1. Otherwise, it resets the action to SIG_DFL and calls the action function with argument signum, and returns the value returned by that function. The range of possible values signum varies (often 1–15 or 1–17).

For an explanation of the terms used in this section, see *attributes*(7).

These functions are available under AIX, DG/UX, HP-UX, SCO, Solaris, Tru64. They are called obsolete under most of these systems, and are broken under glibc. Some systems also have *gsignal_r*() and *ssignal_r*().

*kill*(2), *signal*(2), *raise*(3)

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