Description
Create and initialize a mutex. A mutex is used to gain exclusive access to a resource.
Files
os.h/os_mutex.c
Prototype
Arguments
p_mutex
is a pointer to a mutex control block that must be allocated in the application. The user will need to declare a “global” variable as follows, and pass a pointer to this variable to OSMutexCreate():
OS_MUTEX MyMutex;
p_name
is a pointer to an ASCII string used to assign a name to the mutual exclusion semaphore. The name may be displayed by debuggers or µC/Probe.
p_err
is a pointer to a variable that is used to hold an error code:
OS_ERR_NONE
If the call is successful and the mutex has been created.
OS_ERR_CREATE_ISR
If OS_CFG_CALLED_FROM_ISR_CHK_EN set to 1 in os_cfg.h: if attempting to create a mutex from an ISR.
OS_ERR_OBJ_PTR_NULL
If OS_CFG_ARG_CHK_EN is set to 1 in os_cfg.h: if p_mutex is a NULL pointer.
OS_ERR_ILLEGAL_CREATE_RUN_TIME
If OS_SAFETY_CRITICAL_IEC61508 is defined: you called this after calling OSSafetyCriticalStart() and thus you are no longer allowed to create additional kernel objects.
Returned Value
None
Required Configuration
OS_CFG_MUTEX_EN must be enabled in os_cfg.h. Refer to uC-OS-III Configuration Manual
Callers
Application.
Notes/Warnings
- Mutexes must be created before they are used.