public static ReadHandle GetFileInfo(string filename, FileInfoResult* result)

string

FileInfoResult*

This function gets information about the specified file asynchronously without opening the file. On completion of the asynchronous operation, the parameter's FileInfoResult.FileState member reports whether the file exists (FileState.Exists) or not (FileState.Absent). If the file exists, the parameter's FileInfoResult.FileSize member reports the size of the file in bytes. If the file doesn't exist, the size is reported as zero.

does not copy . It stores the pointer and writes the file information through it on a worker thread when the operation completes, which can be after the call returns. Keep the FileInfoResult that refers to valid and pinned until the returned ReadHandle has a status other than ReadStatus.InProgress. Otherwise, the garbage collector can move or free the memory before the write occurs. Until the operation completes, FileInfoResult.FileState has its initial value of FileState.Absent, which is the same value that a missing file produces, so treat the result as final only after the handle completes.

Warning: A statement around the call pins the FileInfoResult only for the duration of its block, not for the asynchronous operation that continues after the block exits. This is a common mistake in methods, where the compiler places locals that outlive an on the managed heap. Pin the memory for the whole operation.