/* ********************************************************************** * Copyright (C) 1997-2001, International Business Machines * Corporation and others. All Rights Reserved. ********************************************************************** * * File UMUTEX.H * * Modification History: * * Date Name Description * 04/02/97 aliu Creation. * 04/07/99 srl rewrite - C interface, multiple mutices * 05/13/99 stephen Changed to umutex (from cmutex) ****************************************************************************** */ #ifndef UMUTEX_H #define UMUTEX_H #include "unicode/utypes.h" /** * Mutex data type. * @internal */ typedef void *UMTX; /* APP_NO_THREADS is an old symbol. We'll honour it if present. */ #ifdef APP_NO_THREADS # define ICU_USE_THREADS 0 #endif /* Default: use threads. */ #ifndef ICU_USE_THREADS # define ICU_USE_THREADS 1 #endif /* * Code within this library which accesses protected data should * instantiate a Mutex object while doing so. Notice that there is * only one coarse-grained lock which applies to this entire library, * so keep locking short and sweet. * * For example: * * void Function(int arg1, int arg2) * { * static Object* foo; // Shared read-write object * Mutex mutex; * foo->Method(); * // When 'mutex' goes out of scope and gets destroyed here * // the lock is released * } * * Note: Do NOT use the form 'Mutex mutex();' as that merely * forward-declares a function returning a Mutex. This is a common * mistake which silently slips through the compiler!! */ /* Lock a mutex. Pass in NULL if you want the (ick) Single Global Mutex. * @param mutex The given mutex to be locked */ U_CAPI void U_EXPORT2 umtx_lock ( UMTX* mutex ); /* Unlock a mutex. Pass in NULL if you want the single global mutex. * @param mutex The given mutex to be unlocked */ U_CAPI void U_EXPORT2 umtx_unlock ( UMTX* mutex ); /* Initialize a mutex. Use it this way: umtx_init( &aMutex ); * ICU Mutexes, aside from the global mutex, must be explicitly initialized * before use. * @param mutex The given mutex to be initialized */ U_CAPI void U_EXPORT2 umtx_init ( UMTX* mutex ); /* Destroy a mutex. This will free the resources of a mutex. Use it this way: umtx_destroy( &aMutex ); * @param mutex The given mutex to be destroyed */ U_CAPI void U_EXPORT2 umtx_destroy( UMTX *mutex ); /* Is a mutex initialized? Use it this way: umtx_isInitialized( &aMutex ); This function is not normally needed. It is more efficient to unconditionally call umtx_init(&aMutex) than it is to check first. * @param mutex The given mutex to be tested */ U_CAPI UBool U_EXPORT2 umtx_isInitialized( UMTX *mutex ); /* * Atomic Increment and Decrement of an int32_t value. * * Return Values: * If the result of the operation is zero, the return zero. * If the result of the operation is not zero, the sign of returned value * is the same as the sign of the result, but the returned value itself may * be different from the result of the operation. */ U_CAPI int32_t U_EXPORT2 umtx_atomic_inc(int32_t *); U_CAPI int32_t U_EXPORT2 umtx_atomic_dec(int32_t *); #endif /*_CMUTEX*/ /*eof*/