Difference between revisions of "REQUIRE ONCE()"

Revision as of 15:15, 14 December 2009

Template:YLM to do Check default file extension cf Essentials:OOPS

Purpose

Load a Recital class or procedure library or a C extension library built with the Recital API

Syntax

REQUIRE_ONCE(<expC>)

See Also

ACLASS(), ADDPROPERTY(), AMEMBERS(), CLASS, CLASS - Methods, CLASS - Parameters, CLASS - Properties, CLASS - Scoping, CLOSE PROCEDURE, COMPOBJ(), CREATEOBJECT(), DEFINE CLASS, DISPLAY CLASSES, DO, DODEFAULT(), FOREACH, FUNCTION, LINK, LIST CLASSES, LIST PROCEDURE, LOADOBJECT(), METHOD, NEWOBJECT(), OBJECT(), PARAMETERS, PRINT_HTML(), PRINT_JSON(), PRINT_R(), PRINT_XML(), PROCEDURE, REMOVEPROPERTY(), REQUIRE(), SAVEOBJECT(), SQL SELECT, SET CLASSLIBRARY, SET LIBRARY, WITH

Description

The REQUIRE_ONCE() function opens the specified Recital class or procedure library or C extension library file if it is not already open, scans the contents of it, and records the names and positions of the procedures and/or classes defined within it. The <expC> is the name of the library file. If the file extension is not stated, '.dll' is assumed on Windows and '.so' on UNIX/Linux. To load a Recital procedure or class library file, the '.prg' or '.dbo' file extension must be included. To load a library that is not in the current directory, the full path must be included. You can place as many classes or procedures as you want in a library file.

C extension libraries in the shared library directory are loaded automatically at the start of a Recital process. The shared library directory location is defined by the DB_LIBDIR environment variable in the recital.conf file.

The SET LIBRARY TO command, without any filename specified, closes all active C extension library files. A closed library file discards any knowledge of where the procedures within reside. The RELEASE LIBRARY <library filename> command can be used to close an individual C extension library file.

The SET PROCEDURE and CLOSE PROCEDURE commands can also be used to handle Recital procedure library files.

The active procedures and functions can be listed with the LIST or DISPLAY PROCEDURE commands.

For full details on using the Recital C extension API, please see the C extension API documentation.

Example

// Open Samples.so C extension API procedure library
require_once("Samples")
// Close pdf.so C extension API procedure library
release library pdf.so
// Close all active C extension API procedure library files
set library to

Products

Recital, Recital Server