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specifies whether the call is to block if the semaphore is not available, or not block.
OS_OPT_PEND_BLOCKING
to block the caller until the semaphore is available or a timeout occurs.
OS_OPT_PEND_NON_BLOCKING
If the semaphore is not available, OSSemPend() will not block but return to the caller with an appropriate error code.
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If OS_CFG_ARG_CHK_EN is set to 1 in os_cfg.h: if opt is not OS_OPT_PEND_NON_BLOCKING or OS_OPT_PEND_BLOCKING.
OS_ERR_PEND_ABORT
if the pend was aborted
OS_ERR_PEND_ISR
If OS_CFG_CALLED_FROM_ISR_CHK_EN set to 1 in os_cfg.h: if this function is called from an ISR.
OS_ERR_PEND_WOULD_BLOCK
if this function is called as specified OS_OPT_PEND_NON_BLOCKING, and the semaphore was not available.
OS_ERR_SCHED_LOCKED
If calling this function when the scheduler is locked.
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