1 # VMS::Stdio - VMS extensions to Perl's stdio calls
3 # Author: Charles Bailey bailey@genetics.upenn.edu
6 # Docs revised: 13-Oct-1998 Dan Sugalski <sugalskd@ous.edu>
15 our $VERSION = '2.44';
16 our @ISA = qw( Exporter DynaLoader IO::File );
17 our @EXPORT = qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY &O_NOWAIT
18 &O_RDONLY &O_RDWR &O_TRUNC &O_WRONLY );
19 our @EXPORT_OK = qw( &binmode &flush &getname &remove &rewind &sync &setdef &tmpnam
20 &vmsopen &vmssysopen &waitfh &writeof );
21 our %EXPORT_TAGS = ( CONSTANTS => [ qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY
22 &O_NOWAIT &O_RDONLY &O_RDWR &O_TRUNC
24 FUNCTIONS => [ qw( &binmode &flush &getname &remove &rewind
25 &setdef &sync &tmpnam &vmsopen &vmssysopen
26 &waitfh &writeof ) ] );
28 bootstrap VMS::Stdio $VERSION;
31 my($constname) = $AUTOLOAD;
32 $constname =~ s/.*:://;
33 if ($constname =~ /^O_/) {
34 my($val) = constant($constname);
35 defined $val or croak("Unknown VMS::Stdio constant $constname");
36 *$AUTOLOAD = sub { $val; }
38 else { # We don't know about it; hand off to IO::File
41 *$AUTOLOAD = eval "sub { shift->IO::File::$constname(\@_) }";
42 croak "Error autoloading IO::File::$constname: $@" if $@;
47 sub DESTROY { close($_[0]); }
56 VMS::Stdio - standard I/O functions via VMS extensions
60 use VMS::Stdio qw( &flush &getname &remove &rewind &setdef &sync
61 &tmpnam &vmsopen &vmssysopen &waitfh &writeof );
62 setdef("new:[default.dir]");
64 $fh = vmsopen("my.file","rfm=var","alq=100",...) or die $!;
66 print $fh "Hello, world!\n";
71 undef $fh; # closes file
72 $fh = vmssysopen("another.file", O_RDONLY | O_NDELAY, 0, "ctx=bin");
73 sysread($fh,$data,128);
76 remove("another.file");
82 This package gives Perl scripts access via VMS extensions to several
83 C stdio operations not available through Perl's CORE I/O functions.
84 The specific routines are described below. These functions are
85 prototyped as unary operators, with the exception of C<vmsopen>
86 and C<vmssysopen>, which can take any number of arguments, and
87 C<tmpnam>, which takes none.
89 All of the routines are available for export, though none are
90 exported by default. All of the constants used by C<vmssysopen>
91 to specify access modes are exported by default. The routines
92 are associated with the Exporter tag FUNCTIONS, and the constants
93 are associated with the Exporter tag CONSTANTS, so you can more
94 easily choose what you'd like to import:
96 # import constants, but not functions
97 use VMS::Stdio; # same as use VMS::Stdio qw( :DEFAULT );
98 # import functions, but not constants
99 use VMS::Stdio qw( !:CONSTANTS :FUNCTIONS );
101 use VMS::Stdio qw( :CONSTANTS :FUNCTIONS );
105 Of course, you can also choose to import specific functions by
108 This package C<ISA> IO::File, so that you can call IO::File
109 methods on the handles returned by C<vmsopen> and C<vmssysopen>.
110 The IO::File package is not initialized, however, until you
111 actually call a method that VMS::Stdio doesn't provide. This
112 is done to save startup time for users who don't wish to use
113 the IO::File methods.
115 B<Note:> In order to conform to naming conventions for Perl
116 extensions and functions, the name of this package was
117 changed to from VMS::stdio to VMS::Stdio as of Perl 5.002, and the names of some
118 routines were changed. For many releases, calls to the old VMS::stdio routines
119 would generate a warning, and then route to the equivalent
120 VMS::Stdio function. This compatibility interface has now been removed.
126 This function causes the file handle to be reopened with the CRTL's
127 carriage control processing disabled; its effect is the same as that
128 of the C<b> access mode in C<vmsopen>. After the file is reopened,
129 the file pointer is positioned as close to its position before the
130 call as possible (I<i.e.> as close as fsetpos() can get it -- for
131 some record-structured files, it's not possible to return to the
132 exact byte offset in the file). Because the file must be reopened,
133 this function cannot be used on temporary-delete files. C<binmode>
134 returns true if successful, and C<undef> if not.
136 Note that the effect of C<binmode> differs from that of the binmode()
137 function on operating systems such as Windows and MSDOS, and is not
138 needed to process most types of file.
142 This function causes the contents of stdio buffers for the specified
143 file handle to be flushed. If C<undef> is used as the argument to
144 C<flush>, all currently open file handles are flushed. Like the CRTL
145 fflush() routine, it does not flush any underlying RMS buffers for the
146 file, so the data may not be flushed all the way to the disk. C<flush>
147 returns a true value if successful, and C<undef> if not.
151 The C<getname> function returns the file specification associated
152 with a Perl I/O handle. If an error occurs, it returns C<undef>.
156 This function deletes the file named in its argument, returning
157 a true value if successful and C<undef> if not. It differs from
158 the CORE Perl function C<unlink> in that it does not try to
159 reset file protection if the original protection does not give
160 you delete access to the file (cf. L<perlvms>). In other words,
161 C<remove> is equivalent to
163 unlink($file) if VMS::Filespec::candelete($file);
167 C<rewind> resets the current position of the specified file handle
168 to the beginning of the file. It's really just a convenience
169 method equivalent in effect to C<seek($fh,0,0)>. It returns a
170 true value if successful, and C<undef> if it fails.
174 This function sets the default device and directory for the process.
175 It is identical to the built-in chdir() operator, except that the change
176 persists after Perl exits. It returns a true value on success, and
177 C<undef> if it encounters an error.
181 This function flushes buffered data for the specified file handle
182 from stdio and RMS buffers all the way to disk. If successful, it
183 returns a true value; otherwise, it returns C<undef>.
187 The C<tmpnam> function returns a unique string which can be used
188 as a filename when creating temporary files. If, for some
189 reason, it is unable to generate a name, it returns C<undef>.
193 The C<vmsopen> function enables you to specify optional RMS arguments
194 to the VMS CRTL when opening a file. Its operation is similar to the built-in
195 Perl C<open> function (see L<perlfunc> for a complete description),
196 but it will only open normal files; it cannot open pipes or duplicate
197 existing I/O handles. Up to 8 optional arguments may follow the
198 file name. These arguments should be strings which specify
199 optional file characteristics as allowed by the CRTL. (See the
200 CRTL reference manual description of creat() and fopen() for details.)
201 If successful, C<vmsopen> returns a VMS::Stdio file handle; if an
202 error occurs, it returns C<undef>.
204 You can use the file handle returned by C<vmsopen> just as you
205 would any other Perl file handle. The class VMS::Stdio ISA
206 IO::File, so you can call IO::File methods using the handle
207 returned by C<vmsopen>. However, C<use>ing VMS::Stdio does not
208 automatically C<use> IO::File; you must do so explicitly in
209 your program if you want to call IO::File methods. This is
210 done to avoid the overhead of initializing the IO::File package
211 in programs which intend to use the handle returned by C<vmsopen>
212 as a normal Perl file handle only. When the scalar containing
213 a VMS::Stdio file handle is overwritten, C<undef>d, or goes
214 out of scope, the associated file is closed automatically.
216 File characteristic options:
222 Sets the allocation quantity for this file
230 Sets the context for the file. Takes one of these arguments:
236 Disables LF to CRLF translation
240 Negates previous setting of C<ctx=noctx>
244 Disables conversion of FORTRAN carriage control
248 Force record-mode access
256 Causes records to be flushed I<only> when the file is closed, or when an
257 explicit flush is done
263 Sets the default extension quantity
267 Sets the default filename string. Used to fill in any missing pieces of the
272 File processing option. Takes one or more of the following (in a
273 comma-separated list if there's more than one)
287 Deferred write; only applicable to files opened for shared access.
291 Delete file on close.
295 Truncate at end-of-file.
299 Create if nonexistent.
307 Submit as command file on close.
311 Spool to system printer on close.
319 Temporary (no file directory).
327 Read check compare operation.
331 Write check compare operation.
335 Maximize version number.
347 Rewind file on close.
351 File can only be processed in a sequential manner.
361 Global buffers requested for the file
377 File record attributes. Takes one of the following:
383 Carriage-return control.
387 Disallow records to span block boundaries.
391 FORTRAN print control.
395 Explicitly forces no carriage control.
405 File record format. Takes one of the following:
411 Fixed-length record format.
415 RMS stream record format.
419 Stream format with line-feed terminator.
423 Stream format with carriage-return terminator.
427 Variable-length record format.
431 Variable-length record with fixed control.
441 Record processing operations. Takes one or more of the following in a
442 comma-separated list:
452 Cancel Ctrl/O (used with Terminal I/O).
456 Capitalizes characters on a read from the terminal.
460 Positions the record stream to the end-of-file for the connect operation
469 Enables use of the prompt specified by pmt=usr-prmpt on input from the
474 Eliminates any information in the type-ahead buffer on a read from the
479 Locks record for a read operation for this process, while allowing other
480 accessors to read the record.
484 Locks record for write.
488 Suppresses echoing of input data on the screen as it is entered on the
493 Indicates that Ctrl/U, Ctrl/R, and DELETE are not to be considered control
494 commands on terminal input, but are to be passed to the application
499 Reads regardless of lock.
503 Returns success status of RMS$_SYNCH if the requested service completes its
512 Allows put/write services using sequential record access mode to occur at
513 any point in the file, truncating the file at that point.
517 Prohibits RMS from automatically unlocking records.
521 Wait until record is available, if currently locked by another stream.
535 The number of retrieval pointers that RMS has to maintain (0 to 127255)
539 File sharing options. Choose one of the following:
545 Allows users to delete.
549 Allows users to read.
553 Allows mainstream access.
557 Prohibits file sharing.
561 Allows users to write.
565 Allows users to update.
569 Allows one or more writers.
581 This function bears the same relationship to the CORE function
582 C<sysopen> as C<vmsopen> does to C<open>. Its first three arguments
583 are the name, access flags, and permissions for the file. Like
584 C<vmsopen>, it takes up to 8 additional string arguments which
585 specify file characteristics. Its return value is identical to
588 The symbolic constants for the mode argument are exported by
589 VMS::Stdio by default, and are also exported by the Fcntl package.
593 This function causes Perl to wait for the completion of an I/O
594 operation on the file handle specified as its argument. It is
595 used with handles opened for asynchronous I/O, and performs its
596 task by calling the CRTL routine fwait().
600 This function writes an EOF to a file handle, if the device driver
601 supports this operation. Its primary use is to send an EOF to a
602 subprocess through a pipe opened for writing without closing the
603 pipe. It returns a true value if successful, and C<undef> if
604 it encounters an error.
610 This document was last revised on 13-Oct-1998, for Perl 5.004, 5.005, and