1 # VMS::Stdio - VMS extensions to Perl's stdio calls
3 # Author: Charles Bailey bailey@genetics.upenn.edu
10 use vars qw( $VERSION @EXPORT @EXPORT_OK %EXPORT_TAGS @ISA );
16 @ISA = qw( Exporter DynaLoader IO::File );
17 @EXPORT = qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY &O_NOWAIT
18 &O_RDONLY &O_RDWR &O_TRUNC &O_WRONLY );
19 @EXPORT_OK = qw( &flush &getname &remove &rewind &sync &tmpnam
20 &vmsopen &vmssysopen &waitfh );
21 %EXPORT_TAGS = ( CONSTANTS => [ qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY
22 &O_NOWAIT &O_RDONLY &O_RDWR &O_TRUNC
24 FUNCTIONS => [ qw( &flush &getname &remove &rewind &sync
25 &tmpnam &vmsopen &vmssysopen &waitfh ) ] );
27 bootstrap VMS::Stdio $VERSION;
30 my($constname) = $AUTOLOAD;
31 $constname =~ s/.*:://;
32 if ($constname =~ /^O_/) {
33 my($val) = constant($constname);
34 defined $val or croak("Unknown VMS::Stdio constant $constname");
36 else { # We don't know about it; hand off to IO::File
40 my($val) = eval "\$obj->IO::File::$constname(@_)";
41 croak "Error autoloading $constname: $@" if $@;
43 *$AUTOLOAD = sub { $val };
47 sub DESTROY { close($_[0]); }
50 ################################################################################
51 # Intercept calls to old VMS::stdio package, complain, and hand off
52 # This will be removed in a future version of VMS::Stdio
57 my($func) = $AUTOLOAD;
59 # Cheap trick: we know DynaLoader has required Carp.pm
60 Carp::carp("Old package VMS::stdio is now VMS::Stdio; please update your code");
61 if ($func eq 'vmsfopen') {
62 Carp::carp("Old function &vmsfopen is now &vmsopen");
63 goto &VMS::Stdio::vmsopen;
65 elsif ($func eq 'fgetname') {
66 Carp::carp("Old function &fgetname is now &getname");
67 goto &VMS::Stdio::getname;
69 else { goto &{"VMS::Stdio::$func"}; }
72 package VMS::Stdio; # in case we ever use AutoLoader
84 use VMS::Stdio qw( &flush &getname &remove &rewind &sync &tmpnam
85 &vmsopen &vmssysopen &waitfh );
87 $fh = vmsopen("my.file","rfm=var","alq=100",...) or die $!;
89 print $fh "Hello, world!\n";
94 undef $fh; # closes file
95 $fh = vmssysopen("another.file", O_RDONLY | O_NDELAY, 0, "ctx=bin");
96 sysread($fh,$data,128);
99 remove("another.file");
103 This package gives Perl scripts access to VMS extensions to several
104 C stdio operations not available through Perl's CORE I/O functions.
105 The specific routines are described below. These functions are
106 prototyped as unary operators, with the exception of C<vmsopen>
107 and C<vmssysopen>, which can take any number of arguments, and
108 C<tmpnam>, which takes none.
110 All of the routines are available for export, though none are
111 exported by default. All of the constants used by C<vmssysopen>
112 to specify access modes are exported by default. The routines
113 are associated with the Exporter tag FUNCTIONS, and the constants
114 are associated with the Exporter tag CONSTANTS, so you can more
115 easily choose what you'd like to import:
117 # import constants, but not functions
118 use VMS::Stdio; # same as use VMS::Stdio qw( :DEFAULT );
119 # import functions, but not constants
120 use VMS::Stdio qw( !:CONSTANTS :FUNCTIONS );
122 use VMS::Stdio qw( :CONSTANTS :FUNCTIONS );
126 Of course, you can also choose to import specific functions by
129 This package C<ISA> IO::File, so that you can call IO::File
130 methods on the handles returned by C<vmsopen> and C<vmssysopen>.
131 The IO::File package is not initialized, however, until you
132 actually call a method that VMS::Stdio doesn't provide. This
133 is doen to save startup time for users who don't wish to use
134 the IO::File methods.
136 B<Note:> In order to conform to naming conventions for Perl
137 extensions and functions, the name of this package has been
138 changed to VMS::Stdio as of Perl 5.002, and the names of some
139 routines have been changed. Calls to the old VMS::stdio routines
140 will generate a warning, and will be routed to the equivalent
141 VMS::Stdio function. This compatibility interface will be
142 removed in a future release of this extension, so please
143 update your code to use the new routines.
147 This function causes the contents of stdio buffers for the specified
148 file handle to be flushed. If C<undef> is used as the argument to
149 C<flush>, all currently open file handles are flushed. Like the CRTL
150 fflush() routine, it does not flush any underlying RMS buffers for the
151 file, so the data may not be flushed all the way to the disk. C<flush>
152 returns a true value if successful, and C<undef> if not.
156 The C<getname> function returns the file specification associated
157 with a Perl I/O handle. If an error occurs, it returns C<undef>.
161 This function deletes the file named in its argument, returning
162 a true value if successful and C<undef> if not. It differs from
163 the CORE Perl function C<unlink> in that it does not try to
164 reset file protection if the original protection does not give
165 you delete access to the file (cf. L<perlvms>). In other words,
166 C<remove> is equivalent to
168 unlink($file) if VMS::Filespec::candelete($file);
172 C<rewind> resets the current position of the specified file handle
173 to the beginning of the file. It's really just a convenience
174 method equivalent in effect to C<seek($fh,0,0)>. It returns a
175 true value if successful, and C<undef> if it fails.
179 This function flushes buffered data for the specified file handle
180 from stdio and RMS buffers all the way to disk. If successful, it
181 returns a true value; otherwise, it returns C<undef>.
185 The C<tmpnam> function returns a unique string which can be used
186 as a filename when creating temporary files. If, for some
187 reason, it is unable to generate a name, it returns C<undef>.
191 The C<vmsopen> function enables you to specify optional RMS arguments
192 to the VMS CRTL when opening a file. It is similar to the built-in
193 Perl C<open> function (see L<perlfunc> for a complete description),
194 but will only open normal files; it cannot open pipes or duplicate
195 existing I/O handles. Up to 8 optional arguments may follow the
196 file name. These arguments should be strings which specify
197 optional file characteristics as allowed by the CRTL. (See the
198 CRTL reference manual description of creat() and fopen() for details.)
199 If successful, C<vmsopen> returns a VMS::Stdio file handle; if an
200 error occurs, it returns C<undef>.
202 You can use the file handle returned by C<vmsfopen> just as you
203 would any other Perl file handle. The class VMS::Stdio ISA
204 IO::File, so you can call IO::File methods using the handle
205 returned by C<vmsopen>. However, C<use>ing VMS::Stdio does not
206 automatically C<use> IO::File; you must do so explicitly in
207 your program if you want to call IO::File methods. This is
208 done to avoid the overhead of initializing the IO::File package
209 in programs which intend to use the handle returned by C<vmsopen>
210 as a normal Perl file handle only. When the scalar containing
211 a VMS::Stdio file handle is overwritten, C<undef>d, or goes
212 out of scope, the associated file is closed automatically.
216 This function bears the same relationship to the CORE function
217 C<sysopen> as C<vmsopen> does to C<open>. Its first three arguments
218 are the name, access flags, and permissions for the file. Like
219 C<vmsopen>, it takes up to 8 additional string arguments which
220 specify file characteristics. Its return value is identical to
223 The symbolic constants for the mode argument are exported by
224 VMS::Stdio by default, and are also exported by the Fcntl package.
228 This function causes Perl to wait for the completion of an I/O
229 operation on the file handle specified as its argument. It is
230 used with handles opened for asynchronous I/O, and performs its
231 task by calling the CRTL routine fwait().
235 This document was last revised on 28-Jan-1996, for Perl 5.002.