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Diffstat (limited to 'lib/FileHandle.pm')
-rw-r--r-- | lib/FileHandle.pm | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/lib/FileHandle.pm b/lib/FileHandle.pm new file mode 100644 index 0000000000..b215147590 --- /dev/null +++ b/lib/FileHandle.pm @@ -0,0 +1,227 @@ +package FileHandle; + +require 5.003; +use strict; +use vars qw($VERSION @ISA @EXPORT @EXPORT_OK); + +$VERSION = "2.00"; + +require IO::File; +@ISA = qw(IO::File); + +@EXPORT = qw(_IOFBF _IOLBF _IONBF); + +@EXPORT_OK = qw( + pipe + + 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 + + print + printf + getline + getlines +); + +# +# Everything we're willing to export, we must first import. +# +import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK; + +# +# Specialized importer for Fcntl magic. +# +sub import { + my $pkg = shift; + my $callpkg = caller; + Exporter::export $pkg, $callpkg, @_; + + # + # If the Fcntl extension is available, + # export its constants. + # + eval { + require Fcntl; + Exporter::export 'Fcntl', $callpkg; + }; +} + +################################################ +# This is the only exported function we define; +# the rest come from other classes. +# + +sub pipe { + my $r = new IO::Handle; + my $w = new IO::Handle; + CORE::pipe($r, $w) or return undef; + ($r, $w); +} + +1; + +__END__ + +=head1 NAME + +FileHandle - supply object methods for filehandles + +=head1 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; + +=head1 DESCRIPTION + +NOTE: This class is now a front-end to the IO::* classes. + +C<FileHandle::new> creates a C<FileHandle>, which is a reference to a +newly created symbol (see the C<Symbol> package). If it receives any +parameters, they are passed to C<FileHandle::open>; if the open fails, +the C<FileHandle> object is destroyed. Otherwise, it is returned to +the caller. + +C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does. +It requires two parameters, which are passed to C<FileHandle::fdopen>; +if the fdopen fails, the C<FileHandle> object is destroyed. +Otherwise, it is returned to the caller. + +C<FileHandle::open> accepts one parameter or two. With one parameter, +it is just a front end for the built-in C<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 C<FileHandle::open> receives a Perl mode string (">", "+<", etc.) +or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic +Perl C<open> operator. + +If C<FileHandle::open> is given a numeric mode, it passes that mode +and the optional permissions value to the Perl C<sysopen> operator. +For convenience, C<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. + +C<FileHandle::fdopen> is like C<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 +C<FileHandle::getpos> returns an opaque value that represents the +current position of the FileHandle, and C<FileHandle::setpos> uses +that value to return to a previously visited position. + +If the C function setvbuf() is available, then C<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 C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer +parameter specifies a scalar variable to use as a buffer. WARNING: A +variable used as a buffer by C<FileHandle::setvbuf> must not be +modified in any way until the FileHandle is closed or until +C<FileHandle::setvbuf> is called again, or memory corruption may +result! + +See L<perlfunc> for complete descriptions of each of the following +supported C<FileHandle> methods, which are just front ends for the +corresponding built-in functions: + + close + fileno + getc + gets + eof + clearerr + seek + tell + +See L<perlvar> for complete descriptions of each of the following +supported C<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: + +=over + +=item $fh->print + +See L<perlfunc/print>. + +=item $fh->printf + +See L<perlfunc/printf>. + +=item $fh->getline + +This works like <$fh> described in L<perlop/"I/O Operators"> +except that it's more readable and can be safely called in an +array context but still returns just one line. + +=item $fh->getlines + +This works like <$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. + +=back + +=head1 SEE ALSO + +The B<IO> extension, +L<perlfunc>, +L<perlop/"I/O Operators">. + +=cut |