[ новости /+++ | форум | теги | ]

NAME

     FileHandle - supply object methods for filehandles



SYNOPSIS
         use FileHandle;

         $fh = new FileHandle;
         if ($fh->open("< file")) {
             print <$fh>;
             $fh->close;
         }

         $fh = new FileHandle "> FOO";
         if (defined $fh) {
             print $fh "bar\n";
             $fh->close;
         }

         $fh = new FileHandle "file", "r";
         if (defined $fh) {
             print <$fh>;
             undef $fh;       # automatically closes the file
         }

         $fh = new FileHandle "file", O_WRONLY|O_APPEND;
         if (defined $fh) {
             print $fh "corge\n";
             undef $fh;       # automatically closes the file
         }

         $pos = $fh->getpos;
         $fh->setpos($pos);

         $fh->setvbuf($buffer_var, _IOLBF, 1024);

         ($readfh, $writefh) = FileHandle::pipe;

         autoflush STDOUT 1;




DESCRIPTION
     NOTE: This class is now a front-end to the IO::* classes.

     `FileHandle::new' creates a `FileHandle', which is a
     reference to a newly created symbol (see the `Symbol'
     package).  If it receives any parameters, they are passed to
     `FileHandle::open'; if the open fails, the `FileHandle'
     object is destroyed.  Otherwise, it is returned to the
     caller.

     `FileHandle::new_from_fd' creates a `FileHandle' like `new'
     does.  It requires two parameters, which are passed to
     `FileHandle::fdopen'; if the fdopen fails, the `FileHandle'
     object is destroyed.  Otherwise, it is returned to the
     caller.

     `FileHandle::open' accepts one parameter or two.  With one
     parameter, it is just a front end for the built-in `open'
     function.  With two parameters, the first parameter is a
     filename that may include whitespace or other special
     characters, and the second parameter is the open mode,
     optionally followed by a file permission value.

     If `FileHandle::open' receives a Perl mode string (">",
     "+<", etc.)  or a POSIX fopen() mode string ("w", "r+",
     etc.), it uses the basic Perl `open' operator.

     If `FileHandle::open' is given a numeric mode, it passes
     that mode and the optional permissions value to the Perl
     `sysopen' operator.  For convenience, `FileHandle::import'
     tries to import the O_XXX constants from the Fcntl module.
     If dynamic loading is not available, this may fail, but the
     rest of FileHandle will still work.

     `FileHandle::fdopen' is like `open' except that its first
     parameter is not a filename but rather a file handle name, a
     FileHandle object, or a file descriptor number.

     If the C functions fgetpos() and fsetpos() are available,
     then `FileHandle::getpos' returns an opaque value that
     represents the current position of the FileHandle, and
     `FileHandle::setpos' uses that value to return to a
     previously visited position.

     If the C function setvbuf() is available, then
     `FileHandle::setvbuf' sets the buffering policy for the
     FileHandle.  The calling sequence for the Perl function is
     the same as its C counterpart, including the macros
     `_IOFBF', `_IOLBF', and `_IONBF', except that the buffer
     parameter specifies a scalar variable to use as a buffer.
     WARNING: A variable used as a buffer by
     `FileHandle::setvbuf' must not be modified in any way until
     the FileHandle is closed or until `FileHandle::setvbuf' is
     called again, or memory corruption may result!

     See the perlfunc manpage for complete descriptions of each
     of the following supported `FileHandle' methods, which are
     just front ends for the corresponding built-in functions:



         close
         fileno
         getc
         gets
         eof
         clearerr
         seek
         tell

     See the perlvar manpage for complete descriptions of each of
     the following supported `FileHandle' methods:

         autoflush
         output_field_separator
         output_record_separator
         input_record_separator
         input_line_number
         format_page_number
         format_lines_per_page
         format_lines_left
         format_name
         format_top_name
         format_line_break_characters
         format_formfeed

     Furthermore, for doing normal I/O you might need these:

     $fh->print
         See the print entry in the perlfunc manpage.

     $fh->printf
         See the printf entry in the perlfunc manpage.

     $fh->getline
         This works like <$fh> described in the I/O Operators
         entry in the perlop manpage except that it's more
         readable and can be safely called in an array context
         but still returns just one line.

     $fh->getlines
         This works like <$fh> when called in an array context to
         read all the remaining lines in a file, except that it's
         more readable.  It will also croak() if accidentally
         called in a scalar context.

     There are many other functions available since FileHandle is
     descended from IO::File, IO::Seekable, and IO::Handle.
     Please see those respective pages for documentation on more
     functions.



SEE ALSO
     The IO extension, the perlfunc manpage, the I/O Operators
     entry in the perlop manpage.









Поиск по тексту MAN-ов: 


























Партнёры:










Хостинг:










Закладки на сайте

Проследить за страницей


Created 1996-2024 by Maxim Chirkov

Добавить, Поддержать, Вебмастеру