pthread_condattr_initのヘルプ・マニュアル／リナックスコマンド

pthread_condattr_initのヘルプ・マニュアル

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PTHREAD_CONDATTR(3) PTHREAD_CONDATTR(3) 名前 pthread_condattr_init, pthread_condattr_destroy - 条件変数作成時の属性書式 #include int pthread_condattr_init(pthread_condattr_t *attr); int pthread_condattr_destroy(pthread_condattr_t *attr); 説明条件変数の属性は条件変数の作成時に、 pthread_cond_init(3) の第 2 引数として条件変数属性オブジェクトを渡すことで指定することができる。 NULL を渡すことは、すべての属性がデフォルト値に設定された条件変数属性オブジェクトを渡すことと同等である。 LinuxThreads の実装では、条件変数の属性には一切対応していない。条件変数の属性に関する関数は POSIX 標準との互換性を保つためだけに用意されている。 pthread_condattr_init は条件変数属性オブジェクト attr を初期化し、すべての属性をデフォルト値に設定する。 pthread_condattr_destroy は条件変数属性オブジェクトを破壊する。破壊したオブジェクトは再び初期化されるまで再使用してはならない。これらの関数は両方とも、 LinuxThreads の実装では何もしない。返り値 pthread_condattr_init および pthread_condattr_destroy は常に 0 を返す。著者 Xavier Leroy 関連項目 pthread_cond_init(3). [ 訳注] LinuxThreads では条件変数をプロセス間で共有することはできない。 glibc-linuxthreads-2.2 以降、次の 2 つの関数が追加されている。 int pthread_condattr_getpshared(const pthread_condattr_t *attr, int *pshared); pshared で指し示される領域に PTHREAD_PROCESS_PRIVATE を格納し、常に 0 を返す。 int pthread_condattr_setpshared(pthread_condattr_t *attr, int pshared); pshared が PTHREAD_PROCESS_PRIVATE および PTHREAD_PROCESS_SHARED のいずれでもない場合、 EINVAL を返す。 pshared が PTHREAD_PROCESS_SHARED の場合、 ENOSYS を返す。それ以外の場合、 0 を返す。 LinuxThreads PTHREAD_CONDATTR(3)

PTHREAD_CONDATTR_DESTROY(3PPOSIX Programmer’s ManuPTHREAD_CONDATTR_DESTROY(3P) PROLOG This manual page is part of the POSIX Programmer’s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME pthread_condattr_destroy, pthread_condattr_init - destroy and initial- ize the condition variable attributes object SYNOPSIS #include int pthread_condattr_destroy(pthread_condattr_t *attr); int pthread_condattr_init(pthread_condattr_t *attr); DESCRIPTION The pthread_condattr_destroy() function shall destroy a condition vari- able attributes object; the object becomes, in effect, uninitialized. An implementation may cause pthread_condattr_destroy() to set the object referenced by attr to an invalid value. A destroyed attr attributes object can be reinitialized using pthread_condattr_init(); the results of otherwise referencing the object after it has been destroyed are undefined. The pthread_condattr_init() function shall initialize a condition vari- able attributes object attr with the default value for all of the attributes defined by the implementation. Results are undefined if pthread_condattr_init() is called specifying an already initialized attr attributes object. After a condition variable attributes object has been used to initial- ize one or more condition variables, any function affecting the attributes object (including destruction) shall not affect any previ- ously initialized condition variables. This volume of IEEE Std 1003.1-2001 requires two attributes, the clock attribute and the process-shared attribute. Additional attributes, their default values, and the names of the asso- ciated functions to get and set those attribute values are implementa- tion-defined. RETURN VALUE If successful, the pthread_condattr_destroy() and pthread_con- dattr_init() functions shall return zero; otherwise, an error number shall be returned to indicate the error. ERRORS The pthread_condattr_destroy() function may fail if: EINVAL The value specified by attr is invalid. The pthread_condattr_init() function shall fail if: ENOMEM Insufficient memory exists to initialize the condition variable attributes object. These functions shall not return an error code of [EINTR]. The following sections are informative. EXAMPLES None. APPLICATION USAGE None. RATIONALE See pthread_attr_init() and pthread_mutex_init(). A process-shared attribute has been defined for condition variables for the same reason it has been defined for mutexes. FUTURE DIRECTIONS None. SEE ALSO pthread_attr_destroy(), pthread_cond_destroy(), pthread_condattr_getp- shared(), pthread_create(), pthread_mutex_destroy(), the Base Defini- tions volume of IEEE Std 1003.1-2001, COPYRIGHT Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . IEEE/The Open Group 2003 PTHREAD_CONDATTR_DESTROY(3P)

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