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NAME

Procure
bid for a semaphore (V39)

SYNOPSIS

Procure(semaphore, bidMessage)
A0 A1

VOID Procure(struct SignalSemaphore *, struct SemaphoreMessage *);

FUNCTION

This function is used to obtain a semaphore in an async manner. Like ObtainSemaphore(), it will obtain a SignalSemaphore for you but unlike ObtainSemaphore(), you will not block until you get the semaphore. Procure() will just post a request for the semaphore and will return. When the semaphore is available (which could be at any time) the bidMessage will ReplyMsg() and you will own the semaphore. This lets you wait on multiple semaphores at once and to continue processing while waiting for the semaphore.

NOTE:
Pre-V39, Procure() and Vacate() did not work correctly.

They also did not operate on SignalSemaphore semaphores. Old (and broken) MessageSemaphore use as of V39 will no longer work.

INPUT

semaphore
The SignalSemaphore that you wish to Procure()

bidMessage- The SemaphoreMessage that you wish replied when

you obtain access to the semaphore. The message's ssm_Semaphore field will point at the semaphore that was obtained. If the ssm_Semaphore field is NULL, the Procure() was aborted via Vacate(). The mn_ReplyPort field of the message must point to a valid message port. To obtain a shared semaphore, the ln_Name field must be set to 1. For an exclusive lock, the ln_Name field must be 0. No other values are valid.

BUGS

Before V39, Procure() and Vacate() used a different semaphore system that was very broken. This new system is only available as of V39 even though the LVOs are the same.

SEE ALSO

ObtainSemaphoreShared(), InitSemaphore(), ReleaseSemaphore(), AttemptSemaphore(), ObtainSemaphoreList(), Vacate(), ObtainSemaphore()