5 use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
12 @EXPORT = qw(_IOFBF _IOLBF _IONBF);
18 output_field_separator
19 output_record_separator
20 input_record_separator
27 format_line_break_characters
37 # Everything we're willing to export, we must first import.
39 import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK;
42 # Some people call "FileHandle::function", so all the functions
43 # that were in the old FileHandle class must be imported, too.
50 [qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
51 eof flush error clearerr setbuf setvbuf _open_mode_string)],
53 [qw(seek tell getpos setpos)],
55 [qw(new new_tmpfile open)]
57 for my $pkg (keys %import) {
58 for my $func (@{$import{$pkg}}) {
59 my $c = *{"${pkg}::$func"}{CODE}
60 or die "${pkg}::$func missing";
67 # Specialized importer for Fcntl magic.
72 Exporter::export $pkg, $callpkg, @_;
75 # If the Fcntl extension is available,
76 # export its constants.
80 Exporter::export 'Fcntl', $callpkg;
84 ################################################
85 # This is the only exported function we define;
86 # the rest come from other classes.
90 my $r = new IO::Handle;
91 my $w = new IO::Handle;
92 CORE::pipe($r, $w) or return undef;
102 FileHandle - supply object methods for filehandles
108 $fh = new FileHandle;
109 if ($fh->open "< file") {
114 $fh = new FileHandle "> FOO";
120 $fh = new FileHandle "file", "r";
123 undef $fh; # automatically closes the file
126 $fh = new FileHandle "file", O_WRONLY|O_APPEND;
129 undef $fh; # automatically closes the file
135 $fh->setvbuf($buffer_var, _IOLBF, 1024);
137 ($readfh, $writefh) = FileHandle::pipe;
143 NOTE: This class is now a front-end to the IO::* classes.
145 C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
146 newly created symbol (see the C<Symbol> package). If it receives any
147 parameters, they are passed to C<FileHandle::open>; if the open fails,
148 the C<FileHandle> object is destroyed. Otherwise, it is returned to
151 C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
152 It requires two parameters, which are passed to C<FileHandle::fdopen>;
153 if the fdopen fails, the C<FileHandle> object is destroyed.
154 Otherwise, it is returned to the caller.
156 C<FileHandle::open> accepts one parameter or two. With one parameter,
157 it is just a front end for the built-in C<open> function. With two
158 parameters, the first parameter is a filename that may include
159 whitespace or other special characters, and the second parameter is
160 the open mode, optionally followed by a file permission value.
162 If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
163 or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
164 Perl C<open> operator.
166 If C<FileHandle::open> is given a numeric mode, it passes that mode
167 and the optional permissions value to the Perl C<sysopen> operator.
168 For convenience, C<FileHandle::import> tries to import the O_XXX
169 constants from the Fcntl module. If dynamic loading is not available,
170 this may fail, but the rest of FileHandle will still work.
172 C<FileHandle::fdopen> is like C<open> except that its first parameter
173 is not a filename but rather a file handle name, a FileHandle object,
174 or a file descriptor number.
176 If the C functions fgetpos() and fsetpos() are available, then
177 C<FileHandle::getpos> returns an opaque value that represents the
178 current position of the FileHandle, and C<FileHandle::setpos> uses
179 that value to return to a previously visited position.
181 If the C function setvbuf() is available, then C<FileHandle::setvbuf>
182 sets the buffering policy for the FileHandle. The calling sequence
183 for the Perl function is the same as its C counterpart, including the
184 macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
185 parameter specifies a scalar variable to use as a buffer. WARNING: A
186 variable used as a buffer by C<FileHandle::setvbuf> must not be
187 modified in any way until the FileHandle is closed or until
188 C<FileHandle::setvbuf> is called again, or memory corruption may
191 See L<perlfunc> for complete descriptions of each of the following
192 supported C<FileHandle> methods, which are just front ends for the
193 corresponding built-in functions:
204 See L<perlvar> for complete descriptions of each of the following
205 supported C<FileHandle> methods:
208 output_field_separator
209 output_record_separator
210 input_record_separator
213 format_lines_per_page
217 format_line_break_characters
220 Furthermore, for doing normal I/O you might need these:
226 See L<perlfunc/print>.
230 See L<perlfunc/printf>.
234 This works like <$fh> described in L<perlop/"I/O Operators">
235 except that it's more readable and can be safely called in an
236 array context but still returns just one line.
240 This works like <$fh> when called in an array context to
241 read all the remaining lines in a file, except that it's more readable.
242 It will also croak() if accidentally called in a scalar context.
250 L<perlop/"I/O Operators">.