is win32 memory mapping thread safe ?

[Reza Shademani]

hi gang! am wondering if win32 memory mapping using "CreateFileMapping" ,"MapViewOfFile" ,"OpenFileMapping" ... is thread safe or not ? i mapped a queue in the file mapping section and i must know if this section is syncronized by default or i've to sync it manually . please give me u'r clues . many thanks in advance ! network security programmer from middle east!

[Iain Clarke Warrior Programmer]

Short answer is no. Its not any more thread safe than un-file-mapped memory. The only real difference is that your changes are occasionally flushed to a file, and that it can be reflected in memory in another process. On another note, if you are using the mapped memory between processes, then any variables in it that are pointers are unlikely to be valid in the other process. So a queue may be dangerous, depending on how you've implemented it. You can get around the synchronisation problems by using named synch objects in both processes. Iain.