Change Mutex lock and unlock API return value to void

Author: rajkan01

rtos/Mutex.h

@@ -84,18 +84,11 @@ class Mutex : private mbed::NonCopyable<Mutex> {
     /**
       Wait until a Mutex becomes available.
 
-      @return  status code that indicates the execution status of the function:
-               @a osOK the mutex has been obtained.
-
       @note You cannot call this function from ISR context.
       @note This function treats RTOS errors as fatal system errors, so it can only return osOK.
             Use of the return value is deprecated, as the return is expected to become void in the future.
      */
-#if MBED_CONF_RTOS_PRESENT
-    osStatus lock();
-#else
-    void lock(); // Value return backwards compatibility not required for non-RTOS
-#endif
+    void lock();
 
     /**
       Wait until a Mutex becomes available.
@@ -150,18 +143,11 @@ class Mutex : private mbed::NonCopyable<Mutex> {
     /**
       Unlock the mutex that has previously been locked by the same thread
 
-      @return status code that indicates the execution status of the function:
-              @a osOK the mutex has been released.
-
       @note You cannot call this function from ISR context.
       @note This function treats RTOS errors as fatal system errors, so it can only return osOK.
             Use of the return value is deprecated, as the return is expected to become void in the future.
      */
-#if MBED_CONF_RTOS_PRESENT
-    osStatus unlock();
-#else
-    void unlock(); // Value return backwards compatibility not required for non-RTOS
-#endif
+    void unlock();
 
     /** Get the owner the this mutex
       @return  the current owner of this mutex.

rtos/source/Mutex.cpp

@@ -57,7 +57,7 @@ void Mutex::constructor(const char *name)
     MBED_ASSERT(_id || mbed_get_error_in_progress());
 }
 
-osStatus Mutex::lock(void)
+void Mutex::lock(void)
 {
     osStatus status = osMutexAcquire(_id, osWaitForever);
     if (osOK == status) {
@@ -66,9 +66,7 @@ osStatus Mutex::lock(void)
 
     if (status != osOK && !mbed_get_error_in_progress()) {
         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_LOCK_FAILED), "Mutex lock failed", status);
-    }
-
-    return osOK;
+    }    
 }
 
 osStatus Mutex::lock(uint32_t millisec)
@@ -127,7 +125,7 @@ bool Mutex::trylock_until(uint64_t millisec)
     }
 }
 
-osStatus Mutex::unlock()
+void Mutex::unlock()
 {
     osStatus status = osMutexRelease(_id);
     if (osOK == status) {
@@ -136,9 +134,7 @@ osStatus Mutex::unlock()
 
     if (status != osOK && !mbed_get_error_in_progress()) {
         MBED_ERROR1(MBED_MAKE_ERROR(MBED_MODULE_KERNEL, MBED_ERROR_CODE_MUTEX_UNLOCK_FAILED), "Mutex unlock failed", status);
-    }
-
-    return status;
+    }    
 }
 
 osThreadId Mutex::get_owner()