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OS_SEM_CTR  OSSemPost (OS_SEM  *p_sem,

                       OS_OPT   opt,

                       OS_ERR  *p_err)

Description

A semaphore is signaled by calling OSSemPost(). If the semaphore value is 0 or more, it is incremented, and OSSemPost() returns to its caller. If tasks are waiting for the semaphore to be signaled, OSSemPost() removes the highest-priority task pending for the semaphore from the waiting list and makes this task ready-to-run. The scheduler is then called to determine if the awakened task is now the highest-priority task that is ready-to-run.

Files

os.h/os_sem.c

Prototype

Arguments

p_sem

is a pointer to the semaphore.

...

The current value of the semaphore count

Required Configuration

OS_CFG_SEM_EN must be enabled in os_cfg.h. Refer to uC-OS-III Configuration Manual

Callers

Application and ISRs.

Notes/Warnings

1. Semaphores must be created before they are used.
2. You can also post to a semaphore from an ISR but the semaphore must be used as a signaling mechanism and not to protect a shared resource.

Example Usage