pthread_cond_init(3C) Standard C Library Functions pthread_cond_init(3C)NAME
pthread_cond_init, pthread_cond_destroy - initialize or destroy condi‐
tion variables
SYNOPSIS
cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>
int pthread_cond_init(pthread_cond_t *restrict cond, const pthread_con‐
dattr_t *restrict attr);
int pthread_cond_destroy(pthread_cond_t *cond);
pthread_cond_t cond= PTHREAD_COND_INITIALIZER;
DESCRIPTION
The function pthread_cond_init() initializes the condition variable
referenced by cond with attributes referenced by attr. If attr is
NULL, the default condition variable attributes are used; the effect is
the same as passing the address of a default condition variable
attributes object. See pthread_condattr_init(3C). Upon successful ini‐
tialization, the state of the condition variable becomes initialized.
Attempting to initialize an already initialized condition variable
results in undefined behavior.
The function pthread_cond_destroy() destroys the given condition vari‐
able specified by cond; the object becomes, in effect, uninitialized.
An implementation may cause pthread_cond_destroy() to set the object
referenced by cond to an invalid value. A destroyed condition variable
object can be re-initialized using pthread_cond_init(); the results of
otherwise referencing the object after it has been destroyed are unde‐
fined.
It is safe to destroy an initialized condition variable upon which no
threads are currently blocked. Attempting to destroy a condition vari‐
able upon which other threads are currently blocked results in unde‐
fined behavior.
In cases where default condition variable attributes are appropriate,
the macro PTHREAD_COND_INITIALIZER can be used to initialize condition
variables that are statically allocated. The effect is equivalent to
dynamic initialization by a call to pthread_cond_init() with parameter
attr specified as NULL, except that no error checks are performed.
RETURN VALUES
If successful, the pthread_cond_init() and pthread_cond_destroy() func‐
tions return 0. Otherwise, an error number is returned to indicate the
error. The EBUSY and EINVAL error checks, if implemented, act as if
they were performed immediately at the beginning of processing for the
function and caused an error return prior to modifying the state of the
condition variable specified by cond.
ERRORS
The pthread_cond_init() function will fail if:
EAGAIN The system lacked the necessary resources (other than
memory) to initialize another condition variable.
ENOMEM Insufficient memory exists to initialize the condition
variable.
The pthread_cond_init() function may fail if:
EBUSY The implementation has detected an attempt to re-ini‐
tialize the object referenced by cond, a previously
initialized, but not yet destroyed, condition variable.
EINVAL The value specified by attr is invalid.
The pthread_cond_destroy() function may fail if:
EBUSY The implementation has detected an attempt to destroy
the object referenced by cond while it is referenced
(for example, while being used in a pthread_cond_wait()
or pthread_cond_timedwait()) by another thread.
EINVAL The value specified by cond is invalid.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Standard │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOpthread_cond_signal(3C), pthread_cond_broadcast(3C),
pthread_cond_wait(3C), pthread_cond_timedwait(3C), pthread_con‐
dattr_init(3C), attributes(5), condition(5), standards(5)SunOS 5.10 23 Mar 2005 pthread_cond_init(3C)
