pthread.3

Linux下的中文输入法

function is used to destroy a thread attributes object.
An implementation may cause
\&\fI\fIpthread_attr_destroy()\fI\fR
to set
\&\fIattr\fR
to an implementation-dependent invalid value.
The behaviour of using the attribute after it has been destroyed is undefined.
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
Upon successful completion,
\&\fI\fIpthread_attr_init()\fI\fR
and
\&\fI\fIpthread_attr_destroy()\fI\fR
return a value of 0.
Otherwise, an error number is returned to indicate the error.
.SH "ERRORS"
.IX Header "ERRORS"
The
\&\fI\fIpthread_attr_init()\fI\fR
function will fail if:
.IP "[\s-1ENOMEM\s0]" 4
.IX Item "[ENOMEM]"
Insufficient memory exists to initialise the thread attributes object.
.PP
These functions will not return an error code of [\s-1EINTR\s0].
.SH "EXAMPLES"
.IX Header "EXAMPLES"
None.
.SH "APPLICATION USAGE"
.IX Header "APPLICATION USAGE"
None.
.SH "FUTURE DIRECTIONS"
.IX Header "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fI\fIpthread_attr_setstackaddr()\fI\fR,
\&\fI\fIpthread_attr_setstacksize()\fI\fR,
\&\fI\fIpthread_attr_setdetachstate()\fI\fR,
\&\fI\fIpthread_create()\fI\fR,
\&\fI<pthread.h\fR>.
.SH "_\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|_"
.IX Header "______________________________________________________________________"
.SH "NAME"
\&\fBpthread_attr_setdetachstate,\fR \fBpthread_attr_getdetachstate\fR
\&\- set and get detachstate attribute
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
#include <pthread.h>
.PP
int pthread_attr_setdetachstate(pthread_attr_t *\fIattr\fR, int \fIdetachstate\fR);
int pthread_attr_getdetachstate(const pthread_attr_t *\fIattr\fR,
int *\fIdetachstate\fR);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The
\&\fIdetachstate\fR
attribute controls whether the thread is created in a detached state.
If the thread is created detached,
then use of the \s-1ID\s0 of the newly created thread by the
\&\fI\fIpthread_detach()\fI\fR
or
\&\fI\fIpthread_join()\fI\fR
function is an error.
.PP
The
\&\fI\fIpthread_attr_setdetachstate()\fI\fR
and
\&\fI\fIpthread_attr_getdetachstate()\fI\fR,
respectively, set and get the
\&\fIdetachstate\fR
attribute in the
\&\fIattr\fR
object.
.PP
The
\&\fIdetachstate\fR
can be set to either \s-1PTHREAD_CREATE_DETACHED\s0 or \s-1PTHREAD_CREATE_JOINABLE\s0.
A value of \s-1PTHREAD_CREATE_DETACHED\s0 causes all threads created with
\&\fIattr\fR
to be in the detached state, whereas using a value of
\&\s-1PTHREAD_CREATE_JOINABLE\s0
causes all threads created with
\&\fIattr\fR
to be in the joinable state.
The default value of the
\&\fIdetachstate\fR
attribute is
\&\s-1PTHREAD_CREATE_JOINABLE\s0 .
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
Upon successful completion,
\&\fI\fIpthread_attr_setdetachstate()\fI\fR
and
\&\fI\fIpthread_attr_getdetachstate()\fI\fR
return a value of 0.
Otherwise, an error number is returned to indicate the error.
.PP
The
\&\fI\fIpthread_attr_getdetachstate()\fI\fR
function stores the value of the
\&\fIdetachstate\fR
attribute in
\&\fIdetachstate\fR
if successful.
.SH "ERRORS"
.IX Header "ERRORS"
The
\&\fI\fIpthread_attr_setdetachstate()\fI\fR
function will fail if:
.IP "[\s-1EINVAL\s0]" 4
.IX Item "[EINVAL]"
The value of
\&\fIdetachstate\fR
was not valid
.PP
These functions will not return an error code of [\s-1EINTR\s0].
.SH "EXAMPLES"
.IX Header "EXAMPLES"
None.
.SH "APPLICATION USAGE"
.IX Header "APPLICATION USAGE"
None.
.SH "FUTURE DIRECTIONS"
.IX Header "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fI\fIpthread_attr_init()\fI\fR,
\&\fI\fIpthread_attr_setstackaddr()\fI\fR,
\&\fI\fIpthread_attr_setstacksize()\fI\fR,
\&\fI\fIpthread_create()\fI\fR,
\&\fI<pthread.h\fR>.
.SH "_\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|_"
.IX Header "______________________________________________________________________"
.SH "NAME"
\&\fBpthread_attr_getguardsize,\fR \fBpthread_attr_setguardsize\fR \-
get or set the thread guardsize attribute
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
#include <pthread.h>
.PP
int pthread_attr_getguardsize(const pthread_attr_t \fI*attr\fR,
size_t \fI*guardsize\fR);
int pthread_attr_setguardsize(pthread_attr_t \fI*attr\fR,
size_t \fIguardsize\fR);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fIguardsize\fR attribute controls the size
of the guard area for the created thread's stack. The \fIguardsize\fR
attribute provides protection against overflow of the
stack pointer. If a thread's stack is created with guard
protection, the implementation allocates extra
memory at the overflow end of the stack as a buffer against
stack overflow of the stack pointer. If an application
overflows into this buffer an error results (possibly
in a \s-1SIGSEGV\s0 signal being delivered to the thread).
.PP
The \fIguardsize\fR attribute is provided to the application
for two reasons:
.IP "1." 4
Overflow protection can potentially
result in wasted system resources. An application that creates a large
number of threads, and which knows its threads will never overflow
their stack, can save system resources by turning off guard areas.
.IP "2." 4
When threads allocate large data structures on the stack,
large guard areas may be needed to detect stack overflow.
.PP
The
\&\fI\fIpthread_attr_getguardsize()\fI\fR
function gets the
\&\fIguardsize\fR attribute in the \fIattr\fR object. This attribute is
returned in the \fIguardsize\fR parameter.
.PP
The
\&\fI\fIpthread_attr_setguardsize()\fI\fR
function sets the
\&\fIguardsize\fR attribute in the \fIattr\fR object. The new value of
this attribute is obtained from the \fIguardsize\fR parameter.
If \fIguardsize\fR is zero, a guard area will not be
provided for threads created with \fIattr\fR. If \fIguardsize\fR is
greater
than zero, a guard area of at least size \fIguardsize\fR
bytes is provided for each thread created with \fIattr\fR.
.PP
A conforming implementation is permitted to round up
the value contained in \fIguardsize\fR to a multiple
of the configurable system variable \s-1PAGESIZE\s0 (see
\&\fI<sys/mman.h\fR>).
If an implementation rounds up the
value of \fIguardsize\fR to a multiple of \s-1PAGESIZE\s0, a call to
\&\fI\fIpthread_attr_getguardsize()\fI\fR
specifying \fIattr\fR will
store in the \fIguardsize\fR parameter the guard size specified by the
previous
\&\fI\fIpthread_attr_setguardsize()\fI\fR
function call.
.PP
The default value of the \fIguardsize\fR attribute is \s-1PAGESIZE\s0 bytes.
The actual value of \s-1PAGESIZE\s0 is
implementation-dependent and may not be the same on all implementations.
.PP
If the \fIstackaddr\fR attribute has been set (that is, the caller
is allocating and managing its own thread stacks), the
\&\fIguardsize\fR attribute is ignored and no protection
will be provided by the implementation. It is the
responsibility of the application to manage stack overflow
along with stack allocation and management in this
case.
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
If successful, the
\&\fI\fIpthread_attr_getguardsize()\fI\fR
and
\&\fI\fIpthread_attr_setguardsize()\fI\fR
functions return zero.
Otherwise, an error number is returned to indicate the error.
.SH "ERRORS"
.IX Header "ERRORS"
The
\&\fI\fIpthread_attr_getguardsize()\fI\fR
and
\&\fI\fIpthread_attr_setguardsize()\fI\fR
functions will fail if:
.IP "[\s-1EINVAL\s0]" 4
.IX Item "[EINVAL]"
The attribute \fIattr\fR is invalid.
.IP "[\s-1EINVAL\s0]" 4
.IX Item "[EINVAL]"
The parameter \fIguardsize\fR is invalid.
.IP "[\s-1EINVAL\s0]" 4
.IX Item "[EINVAL]"
The parameter \fIguardsize\fR contains an invalid value.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
None.
.SH "APPLICATION USAGE"
.IX Header "APPLICATION USAGE"
None.
.SH "FUTURE DIRECTIONS"
.IX Header "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fI<pthread.h\fR>.
.SH "_\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|_"
.IX Header "______________________________________________________________________"
.SH "NAME"
\&\fBpthread_attr_setinheritsched,\fR \fBpthread_attr_getinheritsched\fR
\&\- set and get inheritsched attribute
(\fBREALTIME THREADS\fR)
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
#include <pthread.h>
.PP
int pthread_attr_setinheritsched(pthread_attr_t *\fIattr\fR,
int \fIinheritsched\fR);
int pthread_attr_getinheritsched(const pthread_attr_t *\fIattr\fR,
int *\fIinheritsched\fR);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The functions
\&\fI\fIpthread_attr_setinheritsched()\fI\fR
and
\&\fI\fIpthread_attr_getinheritsched()\fI\fR,
respectively, set and get the
\&\fIinheritsched\fR
attribute in the
\&\fIattr\fR
argument.
.PP
When the attribute objects are used by
\&\fI\fIpthread_create()\fI\fR,
the
\&\fIinheritsched\fR
attribute determines how the other scheduling attributes of
the created thread are to be set:
.IP "\s-1PTHREAD_INHERIT_SCHED\s0" 4
.IX Item "PTHREAD_INHERIT_SCHED"
Specifies that the scheduling policy and associated attributes
are to be inherited from the creating thread, and the scheduling
attributes in this
\&\fIattr\fR
argument are to be ignored.
.IP "\s-1PTHREAD_EXPLICIT_SCHED\s0" 4
.IX Item "PTHREAD_EXPLICIT_SCHED"
Specifies that the scheduling policy and associated attributes
are to be set to the corresponding values from this attribute object.
.PP
The symbols \s-1PTHREAD_INHERIT_SCHED\s0 and \s-1PTHREAD_EXPLICIT_SCHED\s0
are defined in the header
\&\fI<pthread.h\fR>.
.SH "RETURN VALUE"
.IX Header "RETURN VALUE"
If successful, the
\&\fI\fIpthread_attr_setinheritsched()\fI\fR
and
\&\fI\fIpthread_attr_getinheritsched()\fI\fR
functions return zero.
Otherwise, an error number is returned to indicate the error.
.SH "ERRORS"
.IX Header "ERRORS"
The
\&\fI\fIpthread_attr_setinheritsched()\fI\fR
and
\&\fI\fIpthread_attr_getinheritsched()\fI\fR
functions will fail if:
.IP "[\s-1ENOSYS\s0]" 4
.IX Item "[ENOSYS]"
The option _POSIX_THREAD_PRIORITY_SCHEDULING is not defined and the
implementation does not support the function.
.PP
The
\&\fI\fIpthread_attr_setinheritsched()\fI\fR
function may fail if:
.IP "[\s-1EINVAL\s0]" 4
.IX Item "[EINVAL]"
The value of the attribute being set is not valid.
.IP "[\s-1ENOTSUP\s0]" 4
.IX Item "[ENOTSUP]"
An attempt was made to set the attribute to an unsupported value.
.SH "EXAMPLES"
.IX Header "EXAMPLES"
None.
.SH "APPLICATION USAGE"
.IX Header "APPLICATION USAGE"
After these attributes have been set, a thread can be created with
the specified attributes using
\&\fI\fIpthread_create()\fI\fR.
Using these routines does not affect the current running thread.
.SH "FUTURE DIRECTIONS"
.IX Header "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fI\fIpthread_attr_init()\fI\fR,
\&\fI\fIpthread_attr_setscope()\fI\fR,
\&\fI\fIpthread_attr_setschedpolicy()\fI\fR,
\&\fI\fIpthread_attr_setschedparam()\fI\fR,
\&\fI\fIpthread_create()\fI\fR,
\&\fI<pthread.h\fR>,
\&\fI\fIpthread_setschedparam()\fI\fR,
\&\fI<sched.h\fR>.
.SH "_\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|__\|_"
.IX Header "______________________________________________________________________"
.SH "NAME"
\&\fBpthread_attr_setschedparam,\fR \fBpthread_attr_getschedparam\fR
\&\- set and get schedparam attribute
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
#include <pthread.h>
.PP
int pthread_attr_setschedparam(pthread_attr_t *\fIattr\fR,
const struct sched_param *\fIparam\fR);
int pthread_attr_getschedparam(const pthread_attr_t *\fIattr\fR,
struct sched_param *\fIparam\fR);
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The functions
\&\fI\fIpthread_attr_setschedparam()\fI\fR
and
\&\fI\fIpthread_attr_getschedparam()\fI\fR,
respectively, set and get the scheduling parameter
attributes in the
\&\fIattr\fR
argument.