Can you open the same file several times for writing?

Question

We are writing a multi-threaded application that does a bunch of bit-twisting and writes binary data to disk. Is it possible that each stream has std::fopenthe same file for writing at the same time? The reason may be every thread that could do its job and have its own access to the recorded file.

Answer 1

std::fstreamhas functionality defined in terms of the C stdio library. I would be surprised if this was actually indicated, but the most likely behavior when opening the same file twice is several internal buffers associated with the same file descriptor.

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Answer 2

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Answer 3

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Answer 4

Access to I / O is not a parallelizable task (it cannot be, you just cannot send two or more data addresses on the device bus at the same time), so you better implement a queue in which many streams put their pieces of data, and one single consumer actually writes them to disk.