From: Ian AT kiwiplan DOT co DOT nz (Ian Collins) Subject: Signal handling - HELP! 6 Sep 1997 00:20:21 -0700 Approved: cygnus DOT gnu-win32 AT cygnus DOT com Distribution: cygnus Message-ID: <07551A47EAD6D01186430060B025C6F40A6CAE.cygnus.gnu-win32@ntserver.kiwiplan2.co.nz> Mime-Version: 1.0 Content-Type: text/plain Original-To: "'Gnu win32 mailer'" X-Priority: 3 X-Mailer: Internet Mail Service (5.0.1457.3) Original-Sender: owner-gnu-win32 AT cygnus DOT com HELP! Signal handling is not functioning as expected under gnu-win32. When a signal (e.g. SIGALRM) is triggored while in certain system calls (e.g, read), the POSIX signal definition states that after completion of the signal handler, the system call can be made to continue (SA_RESTART) or to return with an error status set. In my application, I require the read system call to RETURN after a SIGALRM. This same code is running as required on many flavours of UNIX, but under GNU-WIN32 (b18), the read system call ALWAYS restarts (i.e, does not return). Following is a small program that illustrates the problem: #include #include main() { extern void callme(); int c; int tm = 2; while (1) { (void) fexec_signal(SIGALRM, tm, callme); if (read(0, c, 1) >0) { printf("Read returned %c\n", c); } else { printf("Read returned negative\n"); } alarm(0); } } int fexec_signal(sig, tm, routine_name) int sig; int tm; void (*routine_name)(); { struct sigaction vec; vec.sa_handler = routine_name; if (sigemptyset(&vec.sa_mask) == -1) return -1; vec.sa_flags = 0; if (sigaction(sig, &vec, NULL) == -1) return -1; if (sig == SIGALRM) alarm(tm); return 0; } void callme() { printf("Timed out\n"); } Many Regards, Ian Collins - For help on using this list (especially unsubscribing), send a message to "gnu-win32-request AT cygnus DOT com" with one line of text: "help". - For help on using this list (especially unsubscribing), send a message to "gnu-win32-request AT cygnus DOT com" with one line of text: "help".