57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
/*
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FUNCTION
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<<__tz_lock>>, <<__tz_unlock>>---lock time zone global variables
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INDEX
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__tz_lock
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INDEX
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__tz_unlock
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ANSI_SYNOPSIS
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#include "local.h"
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void __tz_lock (void);
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void __tz_unlock (void);
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TRAD_SYNOPSIS
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void __tz_lock();
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void __tz_unlock();
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DESCRIPTION
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The <<tzset>> facility functions call these functions when they need to
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ensure the values of global variables. The version of these routines
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supplied in the library use the lock API defined in sys/lock.h. If multiple
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threads of execution can call the time functions and give up scheduling in
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the middle, then you you need to define your own versions of these functions
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in order to safely lock the time zone variables during a call. If you do
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not, the results of <<localtime>>, <<mktime>>, <<ctime>>, and <<strftime>>
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are undefined.
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The lock <<__tz_lock>> may not be called recursively; that is,
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a call <<__tz_lock>> will always lock all subsequent <<__tz_lock>> calls
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until the corresponding <<__tz_unlock>> call on the same thread is made.
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*/
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#include <_ansi.h>
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#include "local.h"
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#include <sys/lock.h>
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#ifndef __SINGLE_THREAD__
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__LOCK_INIT(static, __tz_lock_object);
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#endif
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_VOID
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_DEFUN_VOID (__tz_lock)
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{
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#ifndef __SINGLE_THREAD__
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__lock_acquire(__tz_lock_object);
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#endif
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}
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_VOID
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_DEFUN_VOID (__tz_unlock)
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{
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#ifndef __SINGLE_THREAD__
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__lock_release(__tz_lock_object);
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#endif
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}
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