# VMS::Stdio - VMS extensions to Perl's stdio calls # # Author: Charles Bailey bailey@genetics.upenn.edu # Version: 2.2 # Revised: 19-Jul-1998 # Docs revised: 13-Oct-1998 Dan Sugalski package VMS::Stdio; require 5.002; use vars qw( $VERSION @EXPORT @EXPORT_OK %EXPORT_TAGS @ISA ); use Carp '&croak'; use DynaLoader (); use Exporter (); $VERSION = '2.4'; @ISA = qw( Exporter DynaLoader IO::File ); @EXPORT = qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY &O_NOWAIT &O_RDONLY &O_RDWR &O_TRUNC &O_WRONLY ); @EXPORT_OK = qw( &binmode &flush &getname &remove &rewind &sync &setdef &tmpnam &vmsopen &vmssysopen &waitfh &writeof ); %EXPORT_TAGS = ( CONSTANTS => [ qw( &O_APPEND &O_CREAT &O_EXCL &O_NDELAY &O_NOWAIT &O_RDONLY &O_RDWR &O_TRUNC &O_WRONLY ) ], FUNCTIONS => [ qw( &binmode &flush &getname &remove &rewind &setdef &sync &tmpnam &vmsopen &vmssysopen &waitfh &writeof ) ] ); bootstrap VMS::Stdio $VERSION; sub AUTOLOAD { my($constname) = $AUTOLOAD; $constname =~ s/.*:://; if ($constname =~ /^O_/) { my($val) = constant($constname); defined $val or croak("Unknown VMS::Stdio constant $constname"); *$AUTOLOAD = sub { $val; } } else { # We don't know about it; hand off to IO::File require IO::File; *$AUTOLOAD = eval "sub { shift->IO::File::$constname(\@_) }"; croak "Error autoloading IO::File::$constname: $@" if $@; } goto &$AUTOLOAD; } sub DESTROY { close($_[0]); } ################################################################################ # Intercept calls to old VMS::stdio package, complain, and hand off # This will be removed in a future version of VMS::Stdio package VMS::stdio; sub AUTOLOAD { my($func) = $AUTOLOAD; $func =~ s/.*:://; # Cheap trick: we know DynaLoader has required Carp.pm Carp::carp("Old package VMS::stdio is now VMS::Stdio; please update your code"); if ($func eq 'vmsfopen') { Carp::carp("Old function &vmsfopen is now &vmsopen"); goto &VMS::Stdio::vmsopen; } elsif ($func eq 'fgetname') { Carp::carp("Old function &fgetname is now &getname"); goto &VMS::Stdio::getname; } else { goto &{"VMS::Stdio::$func"}; } } package VMS::Stdio; # in case we ever use AutoLoader 1; __END__ =head1 NAME VMS::Stdio - standard I/O functions via VMS extensions =head1 SYNOPSIS use VMS::Stdio qw( &flush &getname &remove &rewind &setdef &sync &tmpnam &vmsopen &vmssysopen &waitfh &writeof ); setdef("new:[default.dir]"); $uniquename = tmpnam; $fh = vmsopen("my.file","rfm=var","alq=100",...) or die $!; $name = getname($fh); print $fh "Hello, world!\n"; flush($fh); sync($fh); rewind($fh); $line = <$fh>; undef $fh; # closes file $fh = vmssysopen("another.file", O_RDONLY | O_NDELAY, 0, "ctx=bin"); sysread($fh,$data,128); waitfh($fh); close($fh); remove("another.file"); writeof($pipefh); binmode($fh); =head1 DESCRIPTION This package gives Perl scripts access via VMS extensions to several C stdio operations not available through Perl's CORE I/O functions. The specific routines are described below. These functions are prototyped as unary operators, with the exception of C and C, which can take any number of arguments, and C, which takes none. All of the routines are available for export, though none are exported by default. All of the constants used by C to specify access modes are exported by default. The routines are associated with the Exporter tag FUNCTIONS, and the constants are associated with the Exporter tag CONSTANTS, so you can more easily choose what you'd like to import: # import constants, but not functions use VMS::Stdio; # same as use VMS::Stdio qw( :DEFAULT ); # import functions, but not constants use VMS::Stdio qw( !:CONSTANTS :FUNCTIONS ); # import both use VMS::Stdio qw( :CONSTANTS :FUNCTIONS ); # import neither use VMS::Stdio (); Of course, you can also choose to import specific functions by name, as usual. This package C IO::File, so that you can call IO::File methods on the handles returned by C and C. The IO::File package is not initialized, however, until you actually call a method that VMS::Stdio doesn't provide. This is done to save startup time for users who don't wish to use the IO::File methods. B In order to conform to naming conventions for Perl extensions and functions, the name of this package has been changed to VMS::Stdio as of Perl 5.002, and the names of some routines have been changed. Calls to the old VMS::stdio routines will generate a warning, and will be routed to the equivalent VMS::Stdio function. This compatibility interface will be removed in a future release of this extension, so please update your code to use the new routines. =over 4 =item binmode This function causes the file handle to be reopened with the CRTL's carriage control processing disabled; its effect is the same as that of the C access mode in C. After the file is reopened, the file pointer is positioned as close to its position before the call as possible (I as close as fsetpos() can get it -- for some record-structured files, it's not possible to return to the exact byte offset in the file). Because the file must be reopened, this function cannot be used on temporary-delete files. C returns true if successful, and C if not. Note that the effect of C differs from that of the binmode() function on operating systems such as Windows and MSDOS, and is not needed to process most types of file. =item flush This function causes the contents of stdio buffers for the specified file handle to be flushed. If C is used as the argument to C, all currently open file handles are flushed. Like the CRTL fflush() routine, it does not flush any underlying RMS buffers for the file, so the data may not be flushed all the way to the disk. C returns a true value if successful, and C if not. =item getname The C function returns the file specification associated with a Perl I/O handle. If an error occurs, it returns C. =item remove This function deletes the file named in its argument, returning a true value if successful and C if not. It differs from the CORE Perl function C in that it does not try to reset file protection if the original protection does not give you delete access to the file (cf. L). In other words, C is equivalent to unlink($file) if VMS::Filespec::candelete($file); =item rewind C resets the current position of the specified file handle to the beginning of the file. It's really just a convenience method equivalent in effect to C. It returns a true value if successful, and C if it fails. =item setdef This function sets the default device and directory for the process. It is identical to the built-in chdir() operator, except that the change persists after Perl exits. It returns a true value on success, and C if it encounters an error. =item sync This function flushes buffered data for the specified file handle from stdio and RMS buffers all the way to disk. If successful, it returns a true value; otherwise, it returns C. =item tmpnam The C function returns a unique string which can be used as a filename when creating temporary files. If, for some reason, it is unable to generate a name, it returns C. =item vmsopen The C function enables you to specify optional RMS arguments to the VMS CRTL when opening a file. Its operation is similar to the built-in Perl C function (see L for a complete description), but it will only open normal files; it cannot open pipes or duplicate existing I/O handles. Up to 8 optional arguments may follow the file name. These arguments should be strings which specify optional file characteristics as allowed by the CRTL. (See the CRTL reference manual description of creat() and fopen() for details.) If successful, C returns a VMS::Stdio file handle; if an error occurs, it returns C. You can use the file handle returned by C just as you would any other Perl file handle. The class VMS::Stdio ISA IO::File, so you can call IO::File methods using the handle returned by C. However, Cing VMS::Stdio does not automatically C IO::File; you must do so explicitly in your program if you want to call IO::File methods. This is done to avoid the overhead of initializing the IO::File package in programs which intend to use the handle returned by C as a normal Perl file handle only. When the scalar containing a VMS::Stdio file handle is overwritten, Cd, or goes out of scope, the associated file is closed automatically. File characteristic options: =over 2 =item alq=INTEGER Sets the allocation quantity for this file =item bls=INTEGER File blocksize =item ctx=STRING Sets the context for the file. Takes one of these arguments: =over 4 =item bin Disables LF to CRLF translation =item cvt Negates previous setting of C =item nocvt Disables conversion of FORTRAN carriage control =item rec Force record-mode access =item stm Force stream mode =item xplct Causes records to be flushed I when the file is closed, or when an explicit flush is done =back =item deq=INTEGER Sets the default extension quantity =item dna=FILESPEC Sets the default filename string. Used to fill in any missing pieces of the filename passed. =item fop=STRING File processing option. Takes one or more of the following (in a comma-separated list if there's more than one) =over 4 =item ctg Contiguous. =item cbt Contiguous-best-try. =item dfw Deferred write; only applicable to files opened for shared access. =item dlt Delete file on close. =item tef Truncate at end-of-file. =item cif Create if nonexistent. =item sup Supersede. =item scf Submit as command file on close. =item spl Spool to system printer on close. =item tmd Temporary delete. =item tmp Temporary (no file directory). =item nef Not end-of-file. =item rck Read check compare operation. =item wck Write check compare operation. =item mxv Maximize version number. =item rwo Rewind file on open. =item pos Current position. =item rwc Rewind file on close. =item sqo File can only be processed in a sequential manner. =back =item fsz=INTEGER Fixed header size =item gbc=INTEGER Global buffers requested for the file =item mbc=INTEGER Multiblock count =item mbf=INTEGER Bultibuffer count =item mrs=INTEGER Maximum record size =item rat=STRING File record attributes. Takes one of the following: =over 4 =item cr Carriage-return control. =item blk Disallow records to span block boundaries. =item ftn FORTRAN print control. =item none Explicitly forces no carriage control. =item prn Print file format. =back =item rfm=STRING File record format. Takes one of the following: =over 4 =item fix Fixed-length record format. =item stm RMS stream record format. =item stmlf Stream format with line-feed terminator. =item stmcr Stream format with carriage-return terminator. =item var Variable-length record format. =item vfc Variable-length record with fixed control. =item udf Undefined format =back =item rop=STRING Record processing operations. Takes one or more of the following in a comma-separated list: =over 4 =item asy Asynchronous I/O. =item cco Cancel Ctrl/O (used with Terminal I/O). =item cvt Capitalizes characters on a read from the terminal. =item eof Positions the record stream to the end-of-file for the connect operation only. =item nlk Do not lock record. =item pmt Enables use of the prompt specified by pmt=usr-prmpt on input from the terminal. =item pta Eliminates any information in the type-ahead buffer on a read from the terminal. =item rea Locks record for a read operation for this process, while allowing other accessors to read the record. =item rlk Locks record for write. =item rne Suppresses echoing of input data on the screen as it is entered on the keyboard. =item rnf Indicates that Ctrl/U, Ctrl/R, and DELETE are not to be considered control commands on terminal input, but are to be passed to the application program. =item rrl Reads regardless of lock. =item syncsts Returns success status of RMS$_SYNCH if the requested service completes its task immediately. =item tmo Timeout I/O. =item tpt Allows put/write services using sequential record access mode to occur at any point in the file, truncating the file at that point. =item ulk Prohibits RMS from automatically unlocking records. =item wat Wait until record is available, if currently locked by another stream. =item rah Read ahead. =item wbh Write behind. =back =item rtv=INTEGER The number of retrieval pointers that RMS has to maintain (0 to 127255) =item shr=STRING File sharing options. Choose one of the following: =over 4 =item del Allows users to delete. =item get Allows users to read. =item mse Allows mainstream access. =item nil Prohibits file sharing. =item put Allows users to write. =item upd Allows users to update. =item upi Allows one or more writers. =back =item tmo=INTEGER I/O timeout value =back =item vmssysopen This function bears the same relationship to the CORE function C as C does to C. Its first three arguments are the name, access flags, and permissions for the file. Like C, it takes up to 8 additional string arguments which specify file characteristics. Its return value is identical to that of C. The symbolic constants for the mode argument are exported by VMS::Stdio by default, and are also exported by the Fcntl package. =item waitfh This function causes Perl to wait for the completion of an I/O operation on the file handle specified as its argument. It is used with handles opened for asynchronous I/O, and performs its task by calling the CRTL routine fwait(). =item writeof This function writes an EOF to a file handle, if the device driver supports this operation. Its primary use is to send an EOF to a subprocess through a pipe opened for writing without closing the pipe. It returns a true value if successful, and C if it encounters an error. =back =head1 REVISION This document was last revised on 13-Oct-1998, for Perl 5.004, 5.005, and 5.6.0. =cut