CODEWITHSUNDEEP
multithreadingwinapithread-synchronization
Ben
Ben

Reputation: 3440

Synchronize Threads with WINAPI

I would like to synchronize threads with WINAPI calls only but I have no success. The situation is to LOG activities with time and date as soon as my WNDPROC gets a message. The problem is that my WNDPROC needs to write to the log and it will get out of hand since writing to a file takes time. I tried to enter a critical section as soon as WNDPROC starts and leave a critical section as soon as writing to a log is finished, but no luck. How can make them wait for each other?

Upvotes: 0

Views: 287

Answers (1)

Martin James
Martin James

Reputation: 24847

Don't wait - queue.

A Windows message is so small, (within itself:), that copying the entire message into a producer-consumer queue is a reasonable approach. You could raise your own queue class, or you could maybe use the PostThreadMessage() API to copy and queue the received messages to a logger thread:

http://msdn.microsoft.com/en-gb/library/windows/desktop/ms644946%28v=vs.85%29.aspx

The snag with PTM() is that only the message data gets copied and queued up - no time/date. Thge time/date would have to be added in the logger thread when it gets the message copy. Check your requirements to see if this is acceptable. If not, you will have to use a different 'message' struct that has members for both the Windows message and date/time.

Queueing insulates the UI thread from the, possibly lengthy, disk logging write operation and allows extra flexibility to incorporate lazy-writes and other such optimizations, if required.

Upvotes: 2

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