PTHREADONCE(3) BSD Library Functions Manual PTHREADONCE(3)

NAME
     pptthhrreeaaddoonnccee - dynamic package initialization

SYNOPSIS
     ##iinncclluuddee <>

     pthreadoncet oncecontrol = PTHREADONCEINIT;

     int
     pptthhrreeaaddoonnccee(pthreadoncet *oncecontrol, void (*initroutine)(void));

DESCRIPTION
     The first call to pptthhrreeaaddoonnccee() by any thread in a process, with a given
     oncecontrol, will call the iinniittrroouuttiinnee() with no arguments.  Subsequent
     calls to pptthhrreeaaddoonnccee() with the same oncecontrol will not call the
     iinniittrroouuttiinnee().  On return from pptthhrreeaaddoonnccee(), it is guaranteed that
     iinniittrroouuttiinnee() has completed.  The oncecontrol parameter is used to
     determine whether the associated initialization routine has been called.

     The function pptthhrreeaaddoonnccee() is not a cancellation point.  However, if
     iinniittrroouuttiinnee() is a cancellation point and is cancelled, the effect on
     oncecontrol is as if pptthhrreeaaddoonnccee() was never called.

     The constant PTHREADONCEINIT is defined by header .

     The behavior of pptthhrreeaaddoonnccee() is undefined if oncecontrol has automatic
     storage duration or is not initialized by PTHREADONCEINIT.

RETURN VALUES
     If successful,  the pptthhrreeaaddoonnccee() function will return zero.  Otherwise
     an error number will be returned to indicate the error.

EERRRROORRSS
     None.

STANDARDS
     pptthhrreeaaddoonnccee() conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').

BSD                              April 4, 1996                             BSD