sig.c

Purpose

Signal registration, crash backtrace and daemonization helpers.

API Reference

void XUtils_Backtrace(void)

• Arguments:
  • none.
• Does:
  • on Linux, captures up to XUTILS_BACKTRACE_SIZE frames and logs them.
  • on other platforms, effectively does nothing.
• Returns:
  • no return value.

void XUtils_ErrExit(const char *pFmt, ...)

• Arguments:
  • optional printf-style error message.
• Does:
  • logs the formatted message when provided.
  • exits the process with EXIT_FAILURE.
• Returns:
  • no return value because the process terminates.

int XUtils_Daemonize(int bNoChdir, int bNoClose)

• Arguments:
  • bNoChdir: keep current directory when non-zero.
  • bNoClose: keep stdin/stdout/stderr open when non-zero.
• Does:
  • Linux: calls daemon().
  • Windows: starts a detached process and optionally changes directory/closes std handles.
  • other POSIX: double-forks, creates a new session, optionally chdir("/") and redirects stdio to /dev/null.
• Returns:
  • OS success code, usually 0 on success.
  • -1 on failure.

int XSig_Register(int *pSignals, size_t nCount, xsig_cb_t callback)

• Arguments:
  • signal-number array, count and handler callback.
• Does:
  • installs the given handler for each listed signal.
• Returns:
  • 0 on success.
  • on POSIX, the first signal number whose sigaction() registration failed.

int XSig_RegExitSigs(void)

• Arguments:
  • none.
• Does:
  • registers the built-in exit callback for:
    • SIGINT
    • SIGILL
    • SIGSEGV
    • SIGTERM
    • SIGBUS on Linux
• Returns:
  • forwarded result from XSig_Register().

Built-In Handler Behavior

• XSig_Callback() is internal but important:
  • crash-like signals (SIGSEGV, SIGILL, SIGBUS) trigger XUtils_Backtrace()
  • SIGINT and SIGTERM log an informational message
  • every handled signal ends with exit(EXIT_FAILURE)

Important Notes

• This module is intentionally exit-oriented; it is not suitable for recoverable signal handling.