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Programming-Idioms

  • C++
  • Perl

Idiom #199 Truncate a file at the current file position

Truncate a file F at the given file position.

use Path::Tiny qw(path);
my $F = path('F')->openrw;
# ... read some from $F to advance
# position of file handle (not shown) ...
truncate $F, tell $F;

using System.IO;
var F = new FileStream("F", FileMode.Open)
// advance into F here
F.SetLength(F.Position);

Assumes code reads F to advance position into file stream.
New implementation...
< > ⌨
Bart 
my $F = path('F')->openrw;
# ... read some from $F to advance
# position of file handle (not shown) ...
truncate $F, tell $F;

var F = new FileStream("F", FileMode.Open)
// advance into F here
F.SetLength(F.Position);
File(F).openSync(mode: FileMode.write).truncateSync(position);
err := os.Truncate(F, position)
Truncate(F);
F.truncate(F.tell())
F.truncate(F.pos)
let pos = f.stream_position()?;
f.set_len(pos)?;