I needed a truncate function on the `std.stdio.File` object, so I made this function. Does it look okay? Are there any cross-platform improvements you can think of that should be added?


import std.stdio: File;

void truncate(File file, long offset) {
    version (Windows) {
        import core.sys.windows.windows: SetEndOfFile;

        file.seek(offset);
        SetEndOfFile(file.windowsHandle());
    }

    version (Posix) {
        import core.sys.posix.unistd: ftruncate;

        ftruncate(file.fileno(), offset);
    }
}

On Tuesday, 24 July 2018 at 00:15:37 UTC, spikespaz wrote:
> I needed a truncate function on the `std.stdio.File` object, so I made this function. Does it look okay? Are there any cross-platform improvements you can think of that should be added?
>
>
> import std.stdio: File;
>
> void truncate(File file, long offset) {
>     version (Windows) {
>         import core.sys.windows.windows: SetEndOfFile;
>
>         file.seek(offset);
>         SetEndOfFile(file.windowsHandle());
>     }
>
>     version (Posix) {
>         import core.sys.posix.unistd: ftruncate;
>
>         ftruncate(file.fileno(), offset);
>     }
> }

Error handling is completely missing. It should throw a FileException or something when encountering an error, and there can be a lot of errors. Here the list of errno errors that ftruncate() can fail with: EFBIG, EINTR, EINVAL, EIO, EISDIR, EPERM, EROFS, ETXTBSY and EBADF.
for Windows it will be probably quite similar.