?? getenv3.c
字號:
#include <limits.h>#include <string.h>#include <pthread.h>#include <stdlib.h>static pthread_key_t key;static pthread_once_t init_done = PTHREAD_ONCE_INIT;pthread_mutex_t env_mutex = PTHREAD_MUTEX_INITIALIZER;extern char **environ;static voidthread_init(void){ pthread_key_create(&key, free);}char *getenv(const char *name){ int i, len; char *envbuf; pthread_once(&init_done, thread_init); pthread_mutex_lock(&env_mutex); envbuf = (char *)pthread_getspecific(key); if (envbuf == NULL) { envbuf = malloc(ARG_MAX); if (envbuf == NULL) { pthread_mutex_unlock(&env_mutex); return(NULL); } pthread_setspecific(key, envbuf); } len = strlen(name); for (i = 0; environ[i] != NULL; i++) { if ((strncmp(name, environ[i], len) == 0) && (environ[i][len] == '=')) { strcpy(envbuf, &environ[i][len+1]); pthread_mutex_unlock(&env_mutex); return(envbuf); } } pthread_mutex_unlock(&env_mutex); return(NULL);}?? 快捷鍵說明
復制代碼
Ctrl + C
搜索代碼
Ctrl + F
全屏模式
F11
切換主題
Ctrl + Shift + D
顯示快捷鍵
?
增大字號
Ctrl + =
減小字號
Ctrl + -