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According to the C Standard, 7.14.1.1 paragraph 3 [ISO/IEC 9899:2024], if a signal handler returns when it has been entered as a result of a computational exception (that is, with the value of its argument of SIGFPE, SIGILL, SIGSEGV, or any other implementation-defined value corresponding to such an exception) returns, then the behavior is undefined. (See undefined behavior 130.)

When a signal occurs and func points to a function, it is implementation-defined whether the equivalent of signal (sig, SIG_DFL); is executed or the implementation prevents some implementation- defined set of signals (at least including sig) from occurring until the current signal handling has completed; in the case of SIGILL, the implementation may alternatively define that no action is taken. Then the equivalent of (*func)(sig); is executed. If and when the function returns, if the value of sig is SIGFPE, SIGILL, SIGSEGV, or any other implementation-defined value corresponding to a computational exception, the behavior is undefined; otherwise the program will resume execution at the point it was interrupted.

The Portable Operating System Interface (POSIX^®), Base Specifications, Issue 7 [IEEE Std 1003.1:2013], adds SIGBUS to the list of computational exception signal handlers:

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Returning from a computational exception signal handler is undefined behavior.

Automated Detection

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