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NAMEbsd_signal - signal handling with BSD semantics
SYNOPSIS#define _XOPEN_SOURCE /* See feature_test_macros(7) */
typedef void (*sighandler_t)(int);
sighandler_t bsd_signal(int signum, sighandler_t handler);
DESCRIPTIONThe bsd_signal() function takes the same arguments, and performs the same task, as signal(2).
The difference between the two is that bsd_signal() is guaranteed to provide reliable signal semantics, that is: a) the disposition of the signal is not reset to the default when the handler is invoked; b) delivery of further instances of the signal is blocked while the signal handler is executing; and c) if the handler interrupts a blocking system call, then the system call is automatically restarted. A portable application cannot rely on signal(2) to provide these guarantees.
RETURN VALUEThe bsd_signal() function returns the previous value of the signal handler, or SIG_ERR on error.
ERRORSAs for signal(2).
ATTRIBUTESFor an explanation of the terms used in this section, see attributes(7).
CONFORMING TO4.2BSD, POSIX.1-2001. POSIX.1-2008 removes the specification of bsd_signal(), recommending the use of sigaction(2) instead.
NOTESUse of bsd_signal() should be avoided; use sigaction(2) instead.
On modern Linux systems, bsd_signal() and signal(2) are equivalent. But on older systems, signal(2) provided unreliable signal semantics; see signal(2) for details.
The use of sighandler_t is a GNU extension; this type is defined only if the _GNU_SOURCE feature test macro is defined.