This chapter describes the Library utility.
Library enables you to groups individual files into one file. You also can use Library to group together static source code to create copy libraries. Using Library gives you the following advantages:
Whole suites of programs and/or sets of data files can be stored in one library file.
Once the library file is opened, all the files it contains are readily accessible. You access data files in libraries by the usual OPEN, READ, and CLOSE statements; OPEN and CLOSE become logical operations handled by the run-time system rather than the more time-consuming physical operations.
When you change directory you can still access files in a library in the original directory because the library catalog remains in memory.
If an application contains a call to a library not currently on the logged-on drive and the library has been built into your program, the system prompts you to insert the .lbr file.
You invoke Library from the operating system command line; it runs in batch mode. The following sections describe how to invoke Library, how to create a Library batch file and how to access files in libraries.
To invoke Library, enter:
library filename [filename...] [==library-name]
where the parameters are:
||A file to be included in the library, or a library whose contents are to be included in the library, or a library batch file (see below).|
||The library to be saved. If this is not
specified, the library takes the name of the first parameter, thus
can include drive and/or path. If these are unspecified the current
directory is assumed.
If you specify a .lbr library file as a
the new library includes all the files contained in the old library.
For libraries that you are going to create and recreate frequently, you can write a library batch file (.lbt file) which contains the list of files to be included in the library. See the section Creating a Library Batch File below.
If an overlaid program is in a library, all the overlays must be in the same library as the program root segment.
filename can include a library name as
part of the path, you can use the Library utility to copy files from one
or more existing libraries into a new library. You must give the name of
the new library by using the
library $COBDIR/mylib1.lbr/linein.gnt == mylib2.lbr
Batch files can be used with the load function to save you entering filenames individually. To create a batch file, enter the COBOL Editor; type one filename on each line in the file starting at column one; then save the file using a .lbt extension. This file contains the filenames only, not the actual files.
To run a library batch file, enter:
library batch.lbt == library-name
where the parameters are:
||The file you have just created, containing the list of files to be included in the library.|
||As described previously. However, in this
case, if you do not specify
You can prefix any of the filenames with a pathname identifier.
The following program operations obtain access to files in libraries:
Files within libraries can be found only if the library is open. There are several ways to open a library:
Calling a filename without an extension causes all libraries currently opened to be searched for a program of that name. If the program is not found, and a library of that name exists, that library is opened. The program of that name within that library is run.
For example, if a library contains the program myprog.gnt, the root name of the library is also myprog, and there is no program outside of the library with the same name, then a CALL to myprog causes the library to be opened.
The library is left open, so it is added to the list of libraries which will be searched in a future CALL statement.
library-name.lbr. It loads the
catalog of the library into memory, thus making all the files and
entry points that it contains available to the program.
The Directory Facility provides options for calling and canceling libraries explicitly. This can be useful during development and testing. See the chapter Directory Facility for details.
copy "textname.ext" of "library-name.lbr"
from it, and depending on the CANCELLBR directive, leaves it open for
the rest of the compilation, so that the OF phrase can be omitted from
the following COPY statements. See the chapter Directives
for Compiler in your Server Express User's Guide
for information on CANCELLBR.
copy "textname.ext" of "library-name"
is equivalent to the above, since this directive tells the Compiler
that the name after OF in a COPY statement is a
not a path.
filename.ext from it. If the library
does not exist or does not contain the file, a file not found error is
However, we strongly recommend that your applications are not designed to depend upon this behavior.
This restriction also applies to data files which reside in library files. If you cancel a library file that contains a data file which is currently open, and perform further file operations on that file, the results are unpredictable.
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