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Diffstat (limited to 'linuxthreads/man/pthread_attr_init.man')
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diff --git a/linuxthreads/man/pthread_attr_init.man b/linuxthreads/man/pthread_attr_init.man new file mode 100644 index 0000000000..bd5a169242 --- /dev/null +++ b/linuxthreads/man/pthread_attr_init.man @@ -0,0 +1,221 @@ +.TH PTHREAD_ATTR_INIT 3 LinuxThreads + +.XREF pthread_attr_destroy +.XREF pthread_attr_setdetachstate +.XREF pthread_attr_getdetachstate +.XREF pthread_attr_setschedparam +.XREF pthread_attr_getschedparam +.XREF pthread_attr_setschedpolicy +.XREF pthread_attr_getschedpolicy +.XREF pthread_attr_setinheritsched +.XREF pthread_attr_getinheritsched +.XREF pthread_attr_setscope +.XREF pthread_attr_getscope + +.SH NAME +pthread_attr_init, pthread_attr_destroy, pthread_attr_setdetachstate, pthread_attr_getdetachstate, pthread_attr_setschedparam, pthread_attr_getschedparam, pthread_attr_setschedpolicy, pthread_attr_getschedpolicy, pthread_attr_setinheritsched, pthread_attr_getinheritsched, pthread_attr_setscope, pthread_attr_getscope \- thread creation attributes + +.SH SYNOPSIS +#include <pthread.h> + +int pthread_attr_init(pthread_attr_t *attr); + +int pthread_attr_destroy(pthread_attr_t *attr); + +int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate); + +int pthread_attr_getdetachstate(const pthread_attr_t *attr, int *detachstate); + +int pthread_attr_setschedpolicy(pthread_attr_t *attr, int policy); + +int pthread_attr_getschedpolicy(const pthread_attr_t *attr, int *policy); + +int pthread_attr_setschedparam(pthread_attr_t *attr, const struct sched_param *param); + +int pthread_attr_getschedparam(const pthread_attr_t *attr, struct sched_param *param); + +int pthread_attr_setinheritsched(pthread_attr_t *attr, int inherit); + +int pthread_attr_getinheritsched(const pthread_attr_t *attr, int *inherit); + +int pthread_attr_setscope(pthread_attr_t *attr, int scope); + +int pthread_attr_getscope(const pthread_attr_t *attr, int *scope); + +.SH DESCRIPTION + +Setting attributes for threads is achieved by filling a +thread attribute object |attr| of type !pthread_attr_t!, then passing it as +second argument to !pthread_create!(3). Passing !NULL! is equivalent to +passing a thread attribute object with all attributes set to their +default values. + +!pthread_attr_init! initializes the thread attribute object |attr| and +fills it with default values for the attributes. (The default values +are listed below for each attribute.) + +Each attribute |attrname| (see below for a list of all attributes) can +be individually set using the function !pthread_attr_set!|attrname| +and retrieved using the function !pthread_attr_get!|attrname|. + +!pthread_attr_destroy! destroys a thread attribute object, which +must not be reused until it is reinitialized. !pthread_attr_destroy! +does nothing in the LinuxThreads implementation. + +Attribute objects are consulted only when creating a new thread. The +same attribute object can be used for creating several +threads. Modifying an attribute object after a call to +!pthread_create! does not change the attributes of the thread +previously created. + +The following thread attributes are supported: + +.SS detachstate + +Control whether the thread is created in the joinable state (value +!PTHREAD_CREATE_JOINABLE!) or in the detached state +(!PTHREAD_CREATE_DETACHED!). + +Default value: !PTHREAD_CREATE_JOINABLE!. + +In the joinable state, another thread can synchronize on the thread +termination and recover its termination code using !pthread_join!(3), +but some of the thread resources are kept allocated after the thread +terminates, and reclaimed only when another thread performs +!pthread_join!(3) on that thread. + +In the detached state, the thread resources are immediately freed when +it terminates, but !pthread_join!(3) cannot be used to synchronize on +the thread termination. + +A thread created in the joinable state can later be put in the +detached thread using !pthread_detach!(3). + +.SS schedpolicy + +Select the scheduling policy for the thread: one of +!SCHED_OTHER! (regular, non-realtime scheduling), +!SCHED_RR! (realtime, round-robin) or +!SCHED_FIFO! (realtime, first-in first-out). See +!sched_setpolicy!(2) for more information on scheduling policies. + +Default value: !SCHED_OTHER!. + +The realtime scheduling policies !SCHED_RR! and !SCHED_FIFO! are +available only to processes with superuser privileges. + +The scheduling policy of a thread can be changed after creation with +!pthread_setschedparam!(3). + +.SS schedparam + +Contain the scheduling parameters (essentially, the scheduling +priority) for the thread. See !sched_setparam!(2) for more information +on scheduling parameters. + +Default value: priority is 0. + +This attribute is not significant if the scheduling policy is !SCHED_OTHER!; +it only matters for the realtime policies !SCHED_RR! and !SCHED_FIFO!. + +The scheduling priority of a thread can be changed after creation with +!pthread_setschedparam!(3). + +.SS inheritsched + +Indicate whether the scheduling policy and scheduling parameters for +the newly created thread are determined by the values of the +|schedpolicy| and |schedparam| attributes (value +!PTHREAD_EXPLICIT_SCHED!) or are inherited from the parent thread +(value !PTHREAD_INHERIT_SCHED!). + +Default value: !PTHREAD_EXPLICIT_SCHED!. + +.SS scope + +Define the scheduling contention scope for the created thread. The +only value supported in the LinuxThreads implementation is +!PTHREAD_SCOPE_SYSTEM!, meaning that the threads contend for CPU time +with all processes running on the machine. In particular, thread +priorities are interpreted relative to the priorities of all other +processes on the machine. The other value specified by the standard, +!PTHREAD_SCOPE_PROCESS!, means that scheduling contention occurs only +between the threads of the running process: thread priorities are +interpreted relative to the priorities of the other threads of the +process, regardless of the priorities of other processes. +!PTHREAD_SCOPE_PROCESS! is not supported in LinuxThreads. + +Default value: !PTHREAD_SCOPE_SYSTEM!. + +.SH "RETURN VALUE" + +All functions return 0 on success and a non-zero error code on error. +On success, the !pthread_attr_get!|attrname| functions also store the +current value of the attribute |attrname| in the location pointed to +by their second argument. + +.SH ERRORS + +The !pthread_attr_setdetachstate! function returns the following error +codes on error: +.RS +.TP +!EINVAL! +the specified |detachstate| is not one of !PTHREAD_CREATE_JOINABLE! or +!PTHREAD_CREATE_DETACHED!. +.RE + +The !pthread_attr_setschedparam! function returns the following error +codes on error: +.RS +.TP +!EINVAL! +the priority specified in |param| is outside the range of allowed +priorities for the scheduling policy currently in |attr| +(1 to 99 for !SCHED_FIFO! and !SCHED_RR!; 0 for !SCHED_OTHER!). +.RE + +The !pthread_attr_setschedpolicy! function returns the following error +codes on error: +.RS +.TP +!EINVAL! +the specified |policy| is not one of !SCHED_OTHER!, !SCHED_FIFO!, or +!SCHED_RR!. + +.TP +!ENOTSUP! +|policy| is !SCHED_FIFO! or !SCHED_RR!, and the effective user of the +calling process is not super-user. +.RE + +The !pthread_attr_setinheritsched! function returns the following error +codes on error: +.RS +.TP +!EINVAL! +the specified |inherit| is not one of !PTHREAD_INHERIT_SCHED! or +!PTHREAD_EXPLICIT_SCHED!. +.RE + +The !pthread_attr_setscope! function returns the following error +codes on error: +.RS +.TP +!EINVAL! +the specified |scope| is not one of !PTHREAD_SCOPE_SYSTEM! or +!PTHREAD_SCOPE_PROCESS!. + +.TP +!ENOTSUP! +the specified |scope| is !PTHREAD_SCOPE_PROCESS! (not supported). +.RE + +.SH AUTHOR +Xavier Leroy <Xavier.Leroy@inria.fr> + +.SH "SEE ALSO" +!pthread_create!(3), +!pthread_join!(3), +!pthread_detach!(3), +!pthread_setschedparam!(3). |