...
Files
os.h/os_sem.c
Prototype
Code Block |
---|
void OSSemCreate (OS_SEM *p_sem,
CPU_CHAR *p_name,
OS_SEM_CTR cnt,
OS_ERR *p_err) |
Arguments
p_sem
is a pointer to the semaphore control block. It is assumed that storage for the semaphore will be allocated in the application. In other words, you need to declare a “global” variable as follows, and pass a pointer to this variable to OSSemCreate()
:
OS_SEM MySem MySem;
p_name
is a pointer to an ASCII string used to assign a name to the semaphore. The name can be displayed by debuggers or µC/Probe.
...
If OS_CFG_CALLED_FROM_ISR_CHK_EN
set to 1
in DEF_ENABLED
in os_cfg.h
: if you attempted to create a semaphore from an ISR.
OS_ERR_ILLEGAL_OBJCREATE_PTRRUN_NULLTIME
If If OS_CFGSAFETY_ARG_CHK_EN
is set to 1
in os_cfg.h
: if p_sem
is a NULL
pointerCRITICAL_IEC61508
is defined: you called this after calling OSStart()
and thus you are no longer allowed to create additional kernel objects.
OS_ERR_OBJ_PTR_TYPENULL
If OS_CFG_OBJ_TYPEARG_CHK_EN
is set to 1
in DEF_ENABLED
in os_cfg.h
: if p_sem
has been initialized to a different object type.
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.
is a NULL
pointer.
Returned Value
None
Required Configuration
OS_CFG_SEM_EN
must be enabled in os_cfg.h
. Refer to uCµC-OS-III Configuration Manual.
Callers
Application.
Notes/Warnings
- Semaphores must be created before they are used.
Example Usage
Code Block | ||
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| ||
OS_SEM SwSem;
void main (void)
{
OS_ERR err;
:
OSInit(&err); /* Initialize µC/OS-III */
:
:
OSSemCreate(&SwSem, /* Create Switch Semaphore */
"Switch Semaphore",
0,
&err);
/* Check "err" */
:
:
OSStart(&err); /* Start Multitasking */
} |