• spikespaz (15/15) Jul 23 2018 I needed a truncate function on the `std.stdio.File` object, so I
• Patrick Schluter (7/23) Jul 24 2018 Error handling is completely missing. It should throw a

spikespaz <spikespaz outlook.com> writes:

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);
     }
}

Patrick Schluter <Patrick.Schluter bbox.fr> writes:

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.