Function snippetForFileWrite

Tests/Libraries/Async/AsyncTest.cpp:672–724

SC::Result snippetForFileWrite(AsyncEventLoop& eventLoop, Console& console)
{
ThreadPool threadPool;
SC_TRY(threadPool.create(4));
//! [AsyncFileWriteSnippet]
// Assuming an already created (and running) AsyncEventLoop named `eventLoop`
// ...

// Assuming an already created threadPool named `threadPool`
// ...

// Open the file (for write)
FileOpen openMode;
openMode.mode = FileOpen::Write;
openMode.blocking = true; // AsyncFileWrite::Task enables using regular blocking file descriptors
FileDescriptor fd;
SC_TRY(fd.open("MyFile.txt", openMode));

// Create the async file write request
AsyncFileWrite asyncWriteFile;
asyncWriteFile.callback = [&](AsyncFileWrite::Result& res)
{
    size_t writtenBytes = 0;
    if(res.get(writtenBytes))
    {
        console.print("{} bytes have been written", writtenBytes);
    }
};
// Obtain file descriptor handle
SC_TRY(fd.get(asyncWriteFile.handle, Result::Error("Invalid Handle")));
asyncWriteFile.buffer = StringView("test").toCharSpan();
// Vectorized writes: use proper start overload or set
// AsyncFileWrite::buffers and AsyncFileWrite::singleBuffer = false
    
// Start the operation in a thread pool
AsyncTaskSequence asyncFileTask;
SC_TRY(asyncWriteFile.executeOn(asyncFileTask, threadPool));
SC_TRY(asyncWriteFile.start(eventLoop));

// Execute another file write AFTER the previous one is finished on the same threadPool
AsyncFileWrite asyncWriteFileLater;
asyncWriteFileLater.buffer = StringView("AFTER").toCharSpan();
SC_TRY(asyncWriteFileLater.executeOn(asyncFileTask, threadPool));
SC_TRY(asyncWriteFile.start(eventLoop));

// Alternatively if the file is opened with blocking == false, AsyncFileRead can be omitted
// but the operation will not be fully async on regular (buffered) files, except on io_uring.
//
// SC_TRY(asyncWriteFile.start(eventLoop));
//! [AsyncFileWriteSnippet]
SC_TRY(eventLoop.run());
return Result(true);
}

// clang-format on
} // namespace SC