pthread_cond_init(3)					     Library Functions Manual					      pthread_cond_init(3)

NAME

       pthread_cond_init - Initializes a condition variable.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int pthread_cond_init(
			pthread_cond_t		  *cond,
			const pthread_condattr_t  *attr);

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       IEEE Std 1003.1c-1995, POSIX System Application Program Interface

PARAMETERS

       Condition  variable  to be initialized.	Condition variable attributes object that defines the characteristics of the condition variable to
       be initialized.

DESCRIPTION

       This routine initializes the condition variable (cond) with attributes referenced by attr.  If attr is NULL, the default condition variable
       attributes are used.

       A  condition  variable  is a synchronization object used in conjunction with a mutex.  A mutex controls access to data that is shared among
       threads; a condition variable allows threads to wait for that data to enter a defined state.

       Condition variables are not owned by a particular thread.  Any associated storage is not automatically deallocated when the creating thread
       terminates.

       Use  the DECthreads macro PTHREAD_COND_INITIALIZER to initialize statically allocated condition variables to the default condition variable
       attributes.  To call this macro, enter:

       pthread_cond_t condition = PTHREAD_COND_INITIALIZER

       When statically initialized, a condition variable should not also be using pthread_cond_init(3).  Also, a statically initialized  condition
       variable need not be destroyed using pthread_cond_destroy(3).

       Under  certain  circumstances,  it  might  be  impossible to wait upon a statically initialized condition variable when the process virtual
       address space (or some other memory limit) is nearly exhausted.	In such a  case,  pthread_cond_wait(3)	or  pthread_cond_timedwait(3)  can
       return [ENOMEM].  To avoid this possibility, initialize critical condition variables using pthread_cond_init(3).

RETURN VALUES

       If  an  error  condition occurs, this routine returns an integer value indicating the type of error, the condition variable is not initial-
       ized, and the contents of cond are undefined.  Possible return values are as follows: Successful completion.  The system lacks  the  neces-
       sary  resources to initialize another condition variable, or The system-imposed limit on the total number of condition variables under exe-
       cution by a single user is exceeded.  The implementation has detected an attempt to reinitialize the object referenced by  cond,  a  previ-
       ously  initialized,  but not yet destroyed condition variable.  The value specified by attr is invalid.	Insufficient memory exists to ini-
       tialize the condition variable.

ERRORS

       None

RELATED INFORMATION

       Functions: pthread_cond_broadcast(3), pthread_cond_destroy(3), pthread_cond_signal(3), pthread_cond_timedwait(3), pthread_cond_wait(3)

       Manuals: Guide to DECthreads and Programmer's Guide

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															      pthread_cond_init(3)