home | O'Reilly's CD bookshelfs | FreeBSD | Linux | Cisco | Cisco Exam    

3.2.8 binmode



This function arranges for the file to be treated in binary mode on operating systems that distinguish between binary and text files. It should be called after the open but before any I/O is done on the filehandle. The only way to reset binary mode on a filehandle is to reopen the file.

On systems that distinguish binary mode from text mode, files that are read in text mode have \r\n sequences translated to \n on input and \n translated to \r\n on output. binmode has no effect under UNIX or Plan9. If FILEHANDLE is an expression, the value is taken as the name of the filehandle. The following example shows how a Perl script might prepare to read a word processor file with embedded control codes:

open WP, "$file.wp" or die "Can't open $file.wp: $!\n";
binmode WP;
while (read WP, $buf, 1024) {...}