gsignal(3)

💖 gsignal(3) — library functions manual, bestie edition 💖

okay so bestie, we need to talk about gsignal and ssignal 🫶 this is a page from the Library Functions Manual, and honestly? the whole vibe is "please don't". buckle up.

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✨ NAME ✨

gsignal, ssignal — the software signal facility 💅

📚 LIBRARY 📚

Standard C library (libc, -lc) 🌸

🎀 SYNOPSIS 🎀

#include <signal.h>

typedef typeof(void (int))  *sighandler_t;

[[deprecated]] int gsignal(int signum);

[[deprecated]] sighandler_t ssignal(int signum, sighandler_t action);

🧚 Feature Test Macro Requirements for glibc 🧚

(peep feature_test_macros(7) for the lore, bestie)

gsignal(), ssignal():

• Since glibc 2.19: _DEFAULT_SOURCE
• glibc 2.19 and earlier: _SVID_SOURCE

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💀 DESCRIPTION 💀

Do NOT use these functions under Linux. like, not even a little. 🙈

Due to a historical mistake, under Linux these functions are literally just aliases for raise(3) and signal(2) respectively. so if you were expecting software signal shenanigans, surprise! you got regular ones. it's giving "oops".

Elsewhere, like on System V-like systems, things are different in a lowkey fascinating way — these functions implement software signaling, entirely independent of the classical signal(2) and kill(2) functions. no cap.

• The function ssignal() defines the action to take when the software signal with number signum is raised using the function gsignal(), and it returns the previous such action or SIG_DFL. 💖
• The function gsignal() does the following:
  1. If no action (or the action SIG_DFL) was specified for signum, then it does nothing and returns 0.
  2. If the action SIG_IGN was specified for signum, then it does nothing and returns 1.
  3. 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 for signum varies — often 1–15 or 1–17. so it's not even a fixed thing, iconic behavior honestly 🌈

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🦋 ATTRIBUTES 🦋

for an explanation of the terms used in this section, go read attributes(7) bestie, it's all there. ✨

• gsignal() — Thread safety: MT-Safe
• ssignal() — Thread safety: MT-Safe sigintr

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👑 STANDARDS 👑

None. literally none. that's it, that's the whole section. 💀

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🌸 HISTORY 🌸

These showed up on AIX, DG/UX, HP-UX, SCO, Solaris, Tru64. they're called obsolete under most of these systems, and they're broken under glibc — which is a big yikes but we move. 🙈

Some systems also have gsignal_r() and ssignal_r(). iykyk.

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🫶 SEE ALSO 🫶

• kill(2)
• signal(2)
• raise(3)

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and that's the whole page, bestie ✨ go use raise(3) instead, i'm begging 🎀

mwah 💋 this was page gsignal(3) from Linux man-pages 6.20, dated 2026-02-08. periodt. 👑