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[win32] merge changes#872,873 from maintbranch
[perl5.git] / lib / FileHandle.pm
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1package FileHandle;
2
5f05dabc 3use 5.003_11;
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4use strict;
5use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
6
7$VERSION = "2.00";
8
9require IO::File;
10@ISA = qw(IO::File);
11
12@EXPORT = qw(_IOFBF _IOLBF _IONBF);
13
14@EXPORT_OK = qw(
15 pipe
16
17 autoflush
18 output_field_separator
19 output_record_separator
20 input_record_separator
21 input_line_number
22 format_page_number
23 format_lines_per_page
24 format_lines_left
25 format_name
26 format_top_name
27 format_line_break_characters
28 format_formfeed
29
30 print
31 printf
32 getline
33 getlines
34);
35
36#
37# Everything we're willing to export, we must first import.
38#
39import IO::Handle grep { !defined(&$_) } @EXPORT, @EXPORT_OK;
40
41#
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42# Some people call "FileHandle::function", so all the functions
43# that were in the old FileHandle class must be imported, too.
44#
45{
46 no strict 'refs';
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47
48 my %import = (
49 'IO::Handle' =>
50 [qw(DESTROY new_from_fd fdopen close fileno getc ungetc gets
51 eof flush error clearerr setbuf setvbuf _open_mode_string)],
52 'IO::Seekable' =>
53 [qw(seek tell getpos setpos)],
54 'IO::File' =>
55 [qw(new new_tmpfile open)]
56 );
57 for my $pkg (keys %import) {
58 for my $func (@{$import{$pkg}}) {
59 my $c = *{"${pkg}::$func"}{CODE}
60 or die "${pkg}::$func missing";
61 *$func = $c;
62 }
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63 }
64}
65
66#
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67# Specialized importer for Fcntl magic.
68#
69sub import {
70 my $pkg = shift;
71 my $callpkg = caller;
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72 require Exporter;
73 Exporter::export($pkg, $callpkg, @_);
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74
75 #
76 # If the Fcntl extension is available,
77 # export its constants.
78 #
79 eval {
80 require Fcntl;
63bfca45 81 Exporter::export('Fcntl', $callpkg);
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82 };
83}
84
85################################################
86# This is the only exported function we define;
87# the rest come from other classes.
88#
89
90sub pipe {
91 my $r = new IO::Handle;
92 my $w = new IO::Handle;
93 CORE::pipe($r, $w) or return undef;
94 ($r, $w);
95}
96
c9de509e 97# Rebless standard file handles
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98bless *STDIN{IO}, "FileHandle" if ref *STDIN{IO} eq "IO::Handle";
99bless *STDOUT{IO}, "FileHandle" if ref *STDOUT{IO} eq "IO::Handle";
100bless *STDERR{IO}, "FileHandle" if ref *STDERR{IO} eq "IO::Handle";
c9de509e 101
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1021;
103
104__END__
105
106=head1 NAME
107
108FileHandle - supply object methods for filehandles
109
110=head1 SYNOPSIS
111
112 use FileHandle;
113
114 $fh = new FileHandle;
115 if ($fh->open "< file") {
116 print <$fh>;
117 $fh->close;
118 }
119
120 $fh = new FileHandle "> FOO";
121 if (defined $fh) {
122 print $fh "bar\n";
123 $fh->close;
124 }
125
126 $fh = new FileHandle "file", "r";
127 if (defined $fh) {
128 print <$fh>;
129 undef $fh; # automatically closes the file
130 }
131
132 $fh = new FileHandle "file", O_WRONLY|O_APPEND;
133 if (defined $fh) {
134 print $fh "corge\n";
135 undef $fh; # automatically closes the file
136 }
137
138 $pos = $fh->getpos;
f86702cc 139 $fh->setpos($pos);
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140
141 $fh->setvbuf($buffer_var, _IOLBF, 1024);
142
143 ($readfh, $writefh) = FileHandle::pipe;
144
145 autoflush STDOUT 1;
146
147=head1 DESCRIPTION
148
149NOTE: This class is now a front-end to the IO::* classes.
150
151C<FileHandle::new> creates a C<FileHandle>, which is a reference to a
152newly created symbol (see the C<Symbol> package). If it receives any
153parameters, they are passed to C<FileHandle::open>; if the open fails,
154the C<FileHandle> object is destroyed. Otherwise, it is returned to
155the caller.
156
157C<FileHandle::new_from_fd> creates a C<FileHandle> like C<new> does.
158It requires two parameters, which are passed to C<FileHandle::fdopen>;
159if the fdopen fails, the C<FileHandle> object is destroyed.
160Otherwise, it is returned to the caller.
161
162C<FileHandle::open> accepts one parameter or two. With one parameter,
163it is just a front end for the built-in C<open> function. With two
164parameters, the first parameter is a filename that may include
165whitespace or other special characters, and the second parameter is
166the open mode, optionally followed by a file permission value.
167
168If C<FileHandle::open> receives a Perl mode string (">", "+<", etc.)
169or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
170Perl C<open> operator.
171
172If C<FileHandle::open> is given a numeric mode, it passes that mode
173and the optional permissions value to the Perl C<sysopen> operator.
174For convenience, C<FileHandle::import> tries to import the O_XXX
175constants from the Fcntl module. If dynamic loading is not available,
176this may fail, but the rest of FileHandle will still work.
177
178C<FileHandle::fdopen> is like C<open> except that its first parameter
179is not a filename but rather a file handle name, a FileHandle object,
180or a file descriptor number.
181
182If the C functions fgetpos() and fsetpos() are available, then
183C<FileHandle::getpos> returns an opaque value that represents the
184current position of the FileHandle, and C<FileHandle::setpos> uses
185that value to return to a previously visited position.
186
187If the C function setvbuf() is available, then C<FileHandle::setvbuf>
188sets the buffering policy for the FileHandle. The calling sequence
189for the Perl function is the same as its C counterpart, including the
190macros C<_IOFBF>, C<_IOLBF>, and C<_IONBF>, except that the buffer
191parameter specifies a scalar variable to use as a buffer. WARNING: A
192variable used as a buffer by C<FileHandle::setvbuf> must not be
193modified in any way until the FileHandle is closed or until
194C<FileHandle::setvbuf> is called again, or memory corruption may
195result!
196
197See L<perlfunc> for complete descriptions of each of the following
198supported C<FileHandle> methods, which are just front ends for the
199corresponding built-in functions:
a6006777 200
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201 close
202 fileno
203 getc
204 gets
205 eof
206 clearerr
207 seek
208 tell
209
210See L<perlvar> for complete descriptions of each of the following
211supported C<FileHandle> methods:
212
213 autoflush
214 output_field_separator
215 output_record_separator
216 input_record_separator
217 input_line_number
218 format_page_number
219 format_lines_per_page
220 format_lines_left
221 format_name
222 format_top_name
223 format_line_break_characters
224 format_formfeed
225
226Furthermore, for doing normal I/O you might need these:
227
228=over
229
230=item $fh->print
231
232See L<perlfunc/print>.
233
234=item $fh->printf
235
236See L<perlfunc/printf>.
237
238=item $fh->getline
239
240This works like <$fh> described in L<perlop/"I/O Operators">
241except that it's more readable and can be safely called in an
242array context but still returns just one line.
243
244=item $fh->getlines
245
246This works like <$fh> when called in an array context to
247read all the remaining lines in a file, except that it's more readable.
248It will also croak() if accidentally called in a scalar context.
249
250=back
251
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252There are many other functions available since FileHandle is descended
253from IO::File, IO::Seekable, and IO::Handle. Please see those
254respective pages for documentation on more functions.
255
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256=head1 SEE ALSO
257
258The B<IO> extension,
259L<perlfunc>,
260L<perlop/"I/O Operators">.
261
262=cut