Table of Contents
The library facility is a feature that can be used to structure processes. A library is a program containing one or more library objects that can be accessed by other programs, which are referred to as calling programs. A library object is an object that is shared by a library and one or more user programs and is exported from the library using an export declaration. Exported procedures are called entry points into the library. Unlike a regular program, which is always entered at the beginning, a library can be entered at any entry point.
Libraries provide all the benefits of procedures plus the added advantages that they can be reused and shared by a number of programs. Consolidating logically related functions into a library can make programming easier and program structure more visible. A call on a procedure in a library is equivalent to a call on a procedure in the calling program.
Libraries offer the following improvements over binding:
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Interlanguage communication is significantly improved.
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Standard packages of functions, such as plotting and statistics, need not be copied into any calling programs.
Libraries offer the following improvements over installation intrinsics:
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A library can have its own global files, databases, transaction bases, and so on.
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Libraries can contain initialization and termination code.
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Libraries can themselves call other libraries.
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Individual users can create their own libraries without possessing special privileges.
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Libraries can be written in more languages than can the installation intrinsics.
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More than one version of a library can be in use at a time.
For information about connection libraries, see the Task Management Programming Guide.
