PTHREAD_CONDATTR_GETPSHARED(3C) Standard C Library Functions
NAME
pthread_condattr_getpshared, pthread_condattr_setpshared - get or set
process-shared condition variable attributes
SYNOPSIS
cc -mt [
flag... ]
file... -lpthread [
library... ]
#include <pthread.h>
int pthread_condattr_getpshared(
const pthread_condattr_t *restrict attr,
int *restrict pshared);
int pthread_condattr_setpshared(
pthread_condattr_t *attr,
int pshared);
DESCRIPTION
The
pthread_condattr_getpshared() function obtains the value of the
process-shared attribute from the attributes object referenced by
attr. The
pthread_condattr_setpshared() function is used to set the
process-shared attribute in an initialized attributes object
referenced by
attr.
The
process-shared attribute is set to
PTHREAD_PROCESS_SHARED to
permit a condition variable to be operated upon by any thread that
has access to the memory where the condition variable is allocated,
even if the condition variable is allocated in memory that is shared
by multiple processes. If the
process-shared attribute is
PTHREAD_PROCESS_PRIVATE, the condition variable will only be operated
upon by threads created within the same process as the thread that
initialized the condition variable; if threads of differing processes
attempt to operate on such a condition variable, the behavior is
undefined. The default value of the attribute is
PTHREAD_PROCESS_PRIVATE. Additional attributes, their default values, and the names of the
associated functions to get and set those attribute values are
implementation-dependent.
RETURN VALUES
If successful, the
pthread_condattr_setpshared() function returns
0.
Otherwise, an error number is returned to indicate the error.
If successful, the
pthread_condattr_getpshared() function returns
0 and stores the value of the
process-shared attribute of
attr into the
object referenced by the
pshared parameter. Otherwise, an error
number is returned to indicate the error.
ERRORS
The
pthread_condattr_getpshared() and
pthread_condattr_setpshared() functions may fail if:
EINVAL The value specified by
attr is invalid.
The
pthread_condattr_setpshared() function will fail if:
EINVAL The new value specified for the attribute is outside the
range of legal values for that attribute.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
pthread_cond_init(3C),
pthread_condattr_init(3C),
pthread_create(3C),
pthread_mutex_init(3C),
attributes(7),
standards(7) March 23, 2005
PTHREAD_CONDATTR_GETPSHARED(3C)
