pthread_lock_global_np(3) [osf1 man page]

pthread_lock_global_np(3)				     Library Functions Manual					 pthread_lock_global_np(3)

NAME

       pthread_lock_global_np - Locks the DECthreads global mutex.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int   pthread_lock_global_np(void);

STANDARDS

       None

PARAMETERS

       None

DESCRIPTION

       This  routine locks the DECthreads global mutex.  If the global mutex is currently held by another thread when a thread calls this routine,
       the calling thread waits for the global mutex to become available and then locks it.

       The thread that has locked the global mutex becomes its current owner and remains the owner until the same thread has  unlocked	it.   This
       routine returns with the global mutex in the locked state and with the current thread as the global mutex's current owner.

       Use the DECthreads global mutex when calling a library package that is not designed to run in a multithreaded environment.  Unless the doc-
       umentation for a library function specifically states that it is thread safe, assume that it is not compatible; in other words,	assume	it
       is nonreentrant.

       The  global mutex is one lock.  Any code that calls any function that is not known to be reentrant should use the same lock.  This prevents
       problems resulting from dependencies among threads that call library functions and those functions' calling other functions, and so on.

       The global mutex is a recursive mutex.  A thread that has locked the global mutex can relock it without deadlocking.   The  locking  thread
       must call pthread_unlock_global_np(3) as many times as it called this routine, to allow another thread to lock the global mutex.

RETURN VALUES

       If  an  error condition occurs, this routine returns an integer value indicating the type of error.  Possible return values are as follows:
       Successful completion.

ERRORS

       None

RELATED INFORMATION

       Functions: pthread_unlock_global_np(3)

       Manuals: Guide to DECthreads and Programmer's Guide

       delim off

															 pthread_lock_global_np(3)

pthread_mutexattr_setpshared(3) 			     Library Functions Manual				   pthread_mutexattr_setpshared(3)

NAME

       pthread_mutexattr_setpshared - Sets the process-shared attribute of a mutex attributes object.

LIBRARY

       DECthreads POSIX 1003.1c Library (libpthread.so)

SYNOPSIS

       #include <pthread.h>

       int   pthread_mutexattr_setpshared(
			     pthread_mutexattr_t       *attr,
			     int		       pshared);

PARAMETERS

       Address	of the mutex attributes object whose process-shared attribute is to be set.  Value to set in the process-shared attribute of attr.
       Must be the value PTHREAD_PROCESS_SHARED, to permit access to the mutex in by any thread in any process that can access	the  memory  where
       the  mutex object is allocated, or PTHREAD_PROCESS_PRIVATE, to permit access to the mutex only by threads in the same process as the thread
       that initialized the mutex object.

DESCRIPTION

       This routine uses the value in pshared to set the process-shared attribute in the mutex attributes object referenced by	attr.  The  object
       referenced  by  attr  must  be  initialized  before  this  routine is called. The value of pshared must be either PTHREAD_PROCESS_SHARED or
       PTHREAD_PROCESS_PRIVATE, as defined in the pthread.h include file.

       Setting the process-shared attribute to	PTHREAD_PROCESS_PRIVATE permits a mutex to be operated upon by threads	created  within  the  same
       process	as  the  thread that initialized the mutex.  If threads of differing processes attempt to operate on such a mutex, the behavior is
       undefined.

       The default value of the process-shared attribute of a mutex attributes object is PTHREAD_PROCESS_PRIVATE.

       Setting the process-shared attribute to PTHREAD_PROCESS_SHARED permits a mutex to be operated upon by any thread that  has  access  to  the
       memory where the mutex is allocated, even if the mutex is allocated in memory that is shared by multiple processes.

RETURN VALUES

       If  an  error condition occurs, this routine returns an integer value indicating the type of error.  Possible return values are as follows:
       Successful completion.  The value specified by attr is not a valid mutex attributes object, or the new value specified for the attribute is
       outside the range of legal values for that attribute.

ERRORS

       None

RELATED INFORMATION

       Functions: pthread_mutexattr_getpshared(3), pthread_mutexattr_init(3)

       Manuals: Guide to DECthreads and Programmer's Guide delim off

														   pthread_mutexattr_setpshared(3)