Building Distributed
Applications
Using the Progress AppServer
Advantages of Using Portable R-code
R-code is the intermediate binary code that Progress generates when it compiles Progress 4GL source files. This is the code that is actually run when a procedure is executed. Progress r-code is portable between two dissimilar platforms if it does not contain any code that is dependent on the user interface or a DataServer connection.
Using portable r-code, you can perform application-server development on a platform that is different from your application-server deployment platform. For example, you can compile r-code that is destined to run on a UNIX Application Server process on a Windows 95 4GL client. Further, this means that by compiling on the Windows 95 4GL client, a compiler license for the UNIX platform is not required.
Note the following cautions if you intend to use portable r-code:
The following example compares platform-specific preprocessor directives that will be resolved at compile time with a comparable 4GL code that is resolved at run time.
Preprocessor directive resolved at compile time:
Non-preprocessor 4GL code resolved at run time:
If the code from the first example is compiled on a Windows NT client, the “WIN32" logic would be executed even if the resulting r-code is run by an Application Server process on a UNIX host. Therefore, if there can be multiple deployment platforms for Application Server process code, you should use run-time resolution for platform-specific blocks as the second code example in this section shows.
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