/**************************************************************************** * libs/libc/pthread/pthread_keycreate.c * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #if CONFIG_TLS_NELEM > 0 /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: pthread_destructor ****************************************************************************/ static void pthread_destructor(FAR void *arg) { UNUSED(arg); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: pthread_key_create * * Description: * This function creates a thread-specific data key visible to all threads * in the system. Although the same key value may be used by different * threads, the values bound to the key by pthread_setspecific() are * maintained on a per-thread basis and persist for the life of the calling * thread. * * Upon key creation, the value NULL will be associated with the new key * in all active threads. Upon thread creation, the value NULL will be * associated with all defined keys in the new thread. * * Input Parameters: * key - A pointer to the key to create. * destructor - An optional destructor() function that may be associated * with each key that is invoked when a thread exits. * * Returned Value: * If successful, the pthread_key_create() function will store the newly * created key value at *key and return zero (OK). Otherwise, an error * number will be returned to indicate the error: * * EAGAIN - The system lacked sufficient resources to create another * thread-specific data key, or the system-imposed limit on * the total number of keys pers process {PTHREAD_KEYS_MAX} * has been exceeded * ENOMEM - Insufficient memory exist to create the key. * ****************************************************************************/ int pthread_key_create(FAR pthread_key_t *key, CODE void (*destructor)(FAR void *)) { FAR struct task_info_s *info = task_get_info(); int candidate; int ret; DEBUGASSERT(key != NULL); DEBUGASSERT(info != NULL); /* Search for an unused index. This is done in a critical section here to * avoid concurrent modification of the group TLS index set. */ ret = nxmutex_lock(&info->ta_lock); if (ret < 0) { return -ret; } ret = EAGAIN; for (candidate = 0; candidate < CONFIG_TLS_NELEM; candidate++) { /* Is this candidate index available? */ if (info->ta_tlsdtor[candidate] == NULL) { /* Yes.. allocate the index and break out of the loop */ if (destructor) { info->ta_tlsdtor[candidate] = destructor; } else { info->ta_tlsdtor[candidate] = pthread_destructor; } *key = candidate; ret = OK; break; } } nxmutex_unlock(&info->ta_lock); return ret; } #endif /* CONFIG_TLS_NELEM */