PerlIO::Via

A helper class for PerlIO layers implemented in Perl. PerlIO::Via ships with the Perl 5.8 source kit.

For example, you can use PerlIO::Via to call MIME::Base64::encode_base64() via open():

#!/usr/local/bin/perl -w; use MIME::Base64; open(my $fh, ">Via(MIME::Base64)", "encode_base64");

PerlIO::Via implements the following methods.

CLOSE(fh) 

Returns on success and -1 on error.

EOF(fh) 

Returns end-of-file state. The default behavior is to return a value of FILL() or READ().

ERROR(fh) 

Returns error state.

FILENO(fh) 

Returns a numeric value that represents the Unix-like file descriptor, or -1 if no file descriptor exists.

FILL(fh) 

Returns a string that will be placed in the buffer.

FLUSH(fh) 

Flushes any buffered write data. Returns on success and -1 on error.

POPPED([fh]) 

Removes a layer from PerlIO::Via.

$class->PUSHED([mode [,fh]]) 

Returns an object or the class, or -1 on failure. PUSHED takes optional arguments for file open mode-r, w, w+, etc.-and takes a mandatory filehandle for the PerlIO layer itself.

READ(buffer, len, fh) 

Returns the number of octets in buffer, which must be less than or equal to len.

SEEK(posn, where, fh) 

Returns on success and -1 on error.

TELL(fh) 

Returns the file position, without an available default.

UNREAD(buffer, fh) 

Returns the number of octets from bufferthat have been successfully saved.

WRITE(buffer, fh) 

Returns the number of octets in buffer that have been written.