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[[!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]]


# IRC, freenode, #hurd, 2012-07-29

    <braunr> our setitimer is bugged
    <braunr> it seems doesn't seem to leave a timer disarmed when the interval
      is set to 0
    <braunr> (which means a one shot timer is actually periodic ..)