TOPS-20 Commands Reference Manual


Runs the CREF program, which produces cross-reference listings from files of type .CRF.


@CREF destination-filespec=source-filespec /switch(es)



is the name of the file or device to which you want to send the processed contents of the .CRF file.

Default - LPT:


is the name of the .CRF file you want to process.

Default - the names of all files of type .CRF produced during the current terminal session

/switch is one or more keywords from the following list.
CREF Program Switches
/A Advances magnetic tape reel by one file. You can type this switch more than once in the command string.
/B Backspaces magnetic tape reel by one file. You can type this switch more than once in the command string.
/C Cancels the processing of any switches in your SWITCH.INI file.
/D Restores the processing of any default switches in your SWITCH.INI file.
/H Types the CREF help file. /H is illegal in a SWITCH.INI file.
/K Suppresses Regular Symbol Table in the CREF listing.
/M Suppresses OPDEF/Macro Table in the CREF listing.
/O Includes the Op Code Table in the CREF listing.
/P Preserves an input file with the file type .CRF or .LST. These types of input files are normally deleted.
/R Requests the line number at which the CREF listing is to start. CREF types out "RESTART LISTING AT LINE:", after which you type the line number and press RETURN. If you use an indirect file, CREF looks for the number in the indirect file. /R is most useful for physical (non-spooled) line printers, and is illegal in a SWITCH.INI file.
/S Suppresses the program listing and lists only the tables you select.
/T Skips to the logical end of the magnetic tape.
/W Rewinds the magnetic tape.
/Z Zeroes the DECtape directory. This is a historical switch, and is illegal.


Current .CRF Files

If you have files of type .CRF produced by LOAD-class commands during the current terminal session, the unmodified command CREF produces listings of them and deletes the files. By supplying an argument of the form shown in the Format section above, you can copy the listing for a current .CRF file to another file or device. To run the CREF program yourself when you have current .CRF files, give the command R CREF instead.

.CRF Files From a Previous Session

If your only files of type .CRF (created by the CREF program or one of the LOAD-class commands) were produced during a previous terminal session, the command CREF puts your terminal at command level in the CREF program, symbolized by an asterisk (*). Thus it is equivalent to the command R CREF in this case. See Hints - Further Information, below, for advice on how to proceed.


Producing .CRF Files

You can produce cross-reference files by including the /CREF switch in any LOAD-class command that actually causes a compilation (i.e., is not prevented from doing so by a /RELOCATABLE switch or by the existence of current object files).

Preserving .CRF Files After Processing

Give the /P switch immediately after the CREF command to preserve .CRF files. Ordinarily they are deleted after being sent to an output device or copied into another file.

Further Information

For a brief on-line description of the CREF program, give the HELP CREF command. For more detailed information, see the TOPS-20 User Utilities Guide.

Effect on Memory and Terminal

The CREF command replaces the contents of any unkept forks in memory with the CREF program and leaves your terminal at TOPS-20 command level, or at command level within CREF (denoted by an asterisk prompt [*]).

Related Commands

LOAD-class commands for producing .CRF files


  1. Give the CREF command to obtain a listing of your .CRF file.
    CREF:   TESTF1
  2. Compile two FORTRAN programs, using the /CREF switch to produce .CRF files. Then give the CREF command to obtain listings of these, and use the /P switch to preserve the .CRF files.
    CREF:   TESTF1
    CREF:   TESTF2
  3. Determine what .CRF files you have, then mount a tape. Give the CREF command, and once within the CREF program, have the cross-reference listing produced from one of these files copied onto tape. (The .CRF files are not processed automatically when you give the CREF command because they were produced during a previous terminal session.)
     Total of 2 files
    [Mount Request CRFMAC Queued, Request-ID 128]
    [Tape set CRFMAC, volume CRFMAC mounted]
    [CRFMAC defined as MT3:]
    [CRFXKC 4K core]
    [Tape dismounted, logical name CRFMAC: deleted]