From 59344d6c9615e22ecad1e9860b7e287bd92ea6fa Mon Sep 17 00:00:00 2001 From: Pino Toscano Date: Tue, 19 Jun 2012 00:53:40 +0200 Subject: open_issues/alarm_setitimer: New. --- open_issues/alarm_setitimer.mdwn | 23 +++++++++++++++++++++++ open_issues/alarm_setitimer/alrm.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 55 insertions(+) create mode 100644 open_issues/alarm_setitimer.mdwn create mode 100644 open_issues/alarm_setitimer/alrm.c diff --git a/open_issues/alarm_setitimer.mdwn b/open_issues/alarm_setitimer.mdwn new file mode 100644 index 00000000..99b2d7b6 --- /dev/null +++ b/open_issues/alarm_setitimer.mdwn @@ -0,0 +1,23 @@ +[[!meta copyright="Copyright © 2012 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="alarm/setitimer"]] + +[[!tag open_issue_glibc open_issue_hurd]] + +`setitimer()`, called by `alarm()` when setting a new alarm, it is not able +to disable on its own the timer when the alarm is fired the first time. +On the other hand, manually invoking `alarm(0)` can cancel the running timer +for `SIGALRM`. + +See also the attached file: on other OSes (e.g. Linux) it blocks waiting +for a signal, while on GNU/Hurd it gets a new alarm and exits. + +[[alrm.c]] diff --git a/open_issues/alarm_setitimer/alrm.c b/open_issues/alarm_setitimer/alrm.c new file mode 100644 index 00000000..689020ee --- /dev/null +++ b/open_issues/alarm_setitimer/alrm.c @@ -0,0 +1,32 @@ +#include +#include +#include +#include + +static const char msg[] = "< got alarm\n"; + +static void sighandler(int signo __attribute__((unused))) +{ + write(STDOUT_FILENO, msg, sizeof(msg) - 1); +} + +int main() +{ + struct sigaction sa; + sa.sa_handler = sighandler; + sigemptyset(&sa.sa_mask); + sa.sa_flags = 0; + if (sigaction(SIGALRM, &sa, NULL) == -1) + return 1; + + printf("> alarm in 2 secs...\n"); + alarm(2); + pause(); + + printf("> alarm!\n"); + + pause(); + printf("> got a signal...\n"); + + return 0; +} -- cgit v1.2.3