Mutexes are recommended to correctly handle priority inversion, especially if you use LWIP_CORE_LOCKING . 
◆ sys_mutex_free()
      
        
          | void sys_mutex_free | ( | sys_mutex_t * | mutex | ) |  | 
      
 
Deallocates a mutex. 
- Parameters
- 
  
  
 
 
◆ sys_mutex_lock()
      
        
          | void sys_mutex_lock | ( | sys_mutex_t * | mutex | ) |  | 
      
 
Blocks the thread until the mutex can be grabbed. 
- Parameters
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◆ sys_mutex_new()
      
        
          | err_t sys_mutex_new | ( | sys_mutex_t * | mutex | ) |  | 
      
 
Create a new mutex. Note that mutexes are expected to not be taken recursively by the lwIP code, so both implementation types (recursive or non-recursive) should work. The mutex is allocated to the memory that 'mutex' points to (which can be both a pointer or the actual OS structure). If the mutex has been created, ERR_OK should be returned. Returning any other error will provide a hint what went wrong, but except for assertions, no real error handling is implemented.
- Parameters
- 
  
    | mutex | pointer to the mutex to create |  
 
- Returns
- ERR_OK if successful, another err_t otherwise 
 
 
◆ sys_mutex_set_invalid()
      
        
          | void sys_mutex_set_invalid | ( | sys_mutex_t * | mutex | ) |  | 
      
 
Invalidate a mutex so that sys_mutex_valid() returns 0. ATTENTION: This does NOT mean that the mutex shall be deallocated: sys_mutex_free() is always called before calling this function! This may also be a define, in which case the function is not prototyped. 
 
 
◆ sys_mutex_unlock()
      
        
          | void sys_mutex_unlock | ( | sys_mutex_t * | mutex | ) |  | 
      
 
 
◆ sys_mutex_valid()
      
        
          | int sys_mutex_valid | ( | sys_mutex_t * | mutex | ) |  | 
      
 
Returns 1 if the mutes is valid, 0 if it is not valid. When using pointers, a simple way is to check the pointer for != NULL. When directly using OS structures, implementing this may be more complex. This may also be a define, in which case the function is not prototyped.