Perl 5 version 28.2 documentation
- fcntl FILEHANDLE,FUNCTION,SCALAR
Implements the fcntl(2) function. You'll probably have to say
- use Fcntl;
first to get the correct constant definitions. Argument processing and value returned work just like ioctl below. For example:
You don't have to check for defined on the return from fcntl. Like ioctl, it maps a
0return from the system call into
"0 but true"in Perl. This string is true in boolean context and
0in numeric context. It is also exempt from the normal Argument ... isn't numeric warnings on improper numeric conversions.
Here's an example of setting a filehandle named
$REMOTEto be non-blocking at the system level. You'll have to negotiate $ on your own, though.
Portability issues: fcntl in perlport.