SIGINTERRUPT(3P)

✨ SIGINTERRUPT(3P) ✨

okay bestie, we're in the POSIX Programmer's Manual today 💅 this one's from the 3P section, so it's a POSIX function, not a Linux-specific thing.

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🫶 PROLOG 🫶

so real talk before we start: this manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux at all 😭. iykyk.

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🌸 NAME 🌸

siginterrupt — allow signals to interrupt functions ✨

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🎀 SYNOPSIS 🎀

#include <signal.h>

int siginterrupt(int sig, int flag);

like that's the whole vibe. two ints, one header 💖

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💜 DESCRIPTION 💜

okay so the siginterrupt() function shall change the restart behavior when a function is interrupted by the specified signal. 🦋

and here's the tea — the function siginterrupt(sig, flag) has an effect as if it were implemented exactly like this:

int siginterrupt(int sig, int flag) {
    int ret;
    struct sigaction act;

    (void) sigaction(sig, NULL, &act);
    if (flag)
        act.sa_flags &= ~SA_RESTART;
    else
        act.sa_flags |= SA_RESTART;
    ret = sigaction(sig, &act, NULL);
    return ret;
}

so it's basically a little sigaction() wrapper doing a vibe check on SA_RESTART. if flag is truthy it clears SA_RESTART (&= ~SA_RESTART), and if flag is falsy it sets it (|= SA_RESTART). then it calls sigaction() again to commit. iconic.

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⭐ RETURN VALUE ⭐

Upon successful completion, siginterrupt() shall return 0 🎉 otherwise, -1 shall be returned and errno set to indicate the error. not the slay we wanted but okay.

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🔥 ERRORS 🔥

The siginterrupt() function shall fail if:

• EINVAL — the sig argument is not a valid signal number. 🚫 nope, not a real signal bestie.

The following sections are informative. 👀 (so they're extra credit, not requirements)

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🌈 EXAMPLES 🌈

None. 💀 literally none. move along.

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💅 APPLICATION USAGE 💅

The siginterrupt() function supports programs written to historical system interfaces. so it's giving retro, not giving fresh.

Applications should use the sigaction() with the SA_RESTART flag instead of the obsolescent siginterrupt() function. periodt. siginterrupt() is old news, bestie — it's literally marked obsolescent, use the modern one. 🙈

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🧚 RATIONALE 🧚

None. 💜

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🦋 FUTURE DIRECTIONS 🦋

None. 🌸

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👑 SEE ALSO 👑

• Section 2.4, Signal Concepts, sigaction()
• The Base Definitions volume of POSIX.1‐2017, <signal.h>

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💖 COPYRIGHT 💖

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .

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and that's the whole page bestie 🫶 brought to you by IEEE/The Open Group, dated 2017, page SIGINTERRUPT(3P) — stay signal-safe out there, mwah 💋✨