lwIP（Light Weight IP）协议
- 信号量
信号量结构体：struct sys_semt
struct _sys_sem {
void *sem;
};
err_t sys_sem_new(sys_sem_t *sem, u8_t count) 新建信号量
err_t sys_sem_new(sys_sem_t *sem, u8_t count) //err_t为signed char类型,sys_sem_t为struct sys_semt类型
{
HANDLE new_sem = NULL;
LWIP_ASSERT("sem != NULL", sem != NULL);
new_sem = CreateSemaphore(0, count, 100000, 0); //创建一个信号量，创建出错返回0
LWIP_ASSERT("Error creating semaphore", new_sem != NULL);
if(new_sem != NULL)
{
if (SYS_INITIALIZED()) {
SYS_ARCH_LOCKED(SYS_STATS_INC_USED(sem));
} else {
SYS_STATS_INC_USED(sem);
}
#if LWIP_STATS && SYS_STATS
LWIP_ASSERT("sys_sem_new() counter overflow", lwip_stats.sys.sem.used != 0);
#endif /* LWIP_STATS && SYS_STATS*/
sem->sem = new_sem;
return ERR_OK;
}
/* failed to allocate memory... */
if (SYS_INITIALIZED()) {
SYS_ARCH_LOCKED(SYS_STATS_INC(sem.err));
} else {
SYS_STATS_INC(sem.err);
}
sem->sem = NULL;
return ERR_MEM;
}
void sys_sem_signal(sys_sem_t *sem) 发送信号量
u32_t sys_arch_sem_wait(sys_sem_t *sem, u32_t timeout) 等待信号量
void sys_sem_free(sys_sem_t *sem) 删除信号量
void sys_sem_free(sys_sem_t *sem)
{
/* parameter check */
LWIP_ASSERT("sem != NULL", sem != NULL);
LWIP_ASSERT("sem->sem != NULL", sem->sem != NULL);
LWIP_ASSERT("sem->sem != INVALID_HANDLE_VALUE", sem->sem != INVALID_HANDLE_VALUE);
CloseHandle(sem->sem);
SYS_ARCH_LOCKED(SYS_STATS_DEC(sem.used));
#if LWIP_STATS && SYS_STATS
LWIP_ASSERT("sys_sem_free() closed more than created", lwip_stats.sys.sem.used != (u16_t)-1);
#endif /* LWIP_STATS && SYS_STATS */
sem->sem = NULL;
}
int sys_sem_valid(sys_sem_t *sem) 查询是否可用
void sys_sem_set_invalid(sys_sem_t *sem) 设置为失效
void sys_timeout(u32_t msecs, sys_timeout_handler h, void *arg)//设置一个超时事件
void sys_untimeout(sys_timeout_handler h, void *arg)//删除一个超时事件
- 互斥锁
err_t sys_mutex_new(sys_mutex_t *mutex) 新建锁
void sys_mutex_lock(sys_mutex_t *mutex) 获取锁
void sys_mutex_unlock(sys_mutex_t *mutex) 释放锁
void sys_mutex_free(sys_mutex_t *mutex) 删除锁
int sys_mutex_valid(sys_mutex_t *mutex) 查询锁是否可用
void sys_mutex_set_invalid(sys_mutex_t *mutex) 设置锁为失效
- 创建线程
sys_thread_t sys_thread_new(const char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio)
