777
[LIB] Tag
Program Library
Format
1. Define Search Rules: PREFIX PROGRAM "[LIB:proglib]"
2. Write to File: SAVE "[LIB:proglib]prog"
3. Read into Memory: LOAD "[LIB:proglib]prog"
4. Change Name: RENAME "[LIB:proglib]prog" TO ...
5. Delete from System: ERASE "[LIB:proglib]prog"
Where:
[LIB: ..]
File tag clause informs ProvideX that a file belongs to the program
library, proglib.
prog
Name of program.
proglib
Path and filename of program library.
Note: For use in Windows only. Program libraries cannot be accessed remotely; i.e., the
[WDX] tag is not supported.
Description
The [LIB] tag is used as a prefix to denote that ProvideX is to access programs in a
program library, a single keyed file/library where each record contains the object for
a program stored within.
Saving/loading programs from a single file reduces OS file searching and security
checking, and can improve system performance. Program libraries also make it
easier for application developers to ship and install applications. Fundamentally,
program libraries are transparent to applications and are handled much the same
way as directories.
The pathname for a program library is indicated as part of the prefix tag, following the
colon: [LIB:proglib]. The actual program name follows the prefix. For example, if the
program PROG01 is in the library /usr/myappl/proglib it would be referenced as
[LIB:/usr/myappl/proglib]PROG01.
To simplify access to libraries, they can also be defined in a PREFIX (generally a
program prefix); e.g., PREFIX PROGRAM "[LIB:/usr/myappl/proglib]".
Cached Libraries
The system automatically maintains a list of open program libraries. Libraries are kept
open if any programs within a library are in use. In addition, the system maintains a
cache of opened program libraries. By default the number of cached program libraries
is 10; however, this is alterable by setting the 'PL'= System Parameter, p.677. Program
libraries would be closed on a START, QUIT, or whenever 'PL' is changed.