Invoking the Resource Recovery Services attachment facility

The Resource Recovery Services attachment facility (RRSAF) enables your program to communicate with Db2. Invoke RRSAF as an alternative to invoking CAF or when using stored procedures that run in a WLM-established address space. RRSAF has more capabilities than CAF.

To invoke RRSAF:

1. Perform one of the following actions:
   • Explicitly invoke RRSAF by including in your program CALL DSNRLI statements with the appropriate options.

     The first option is an RRSAF connection function, which describes the action that you want RRSAF to take. The effect of any function depends in part on what functions the program has already performed.

     To code RRSAF functions in C, COBOL, Fortran, or PL/I, follow the individual language's rules for making calls to assembler language routines. Specify the return code and reason code parameters in the parameter list for each RRSAF call.

     Requirement: For C, C++, and PL/I applications, you must also include in your program the compiler directives that are listed in the following table, because DSNRLI is an assembler language program.

     Table 1. Compiler directives to include in C, C++, and PL/I applications that contain CALL DSNRLI statements

     Language	Compiler directive to include
     C	#pragma linkage(dsnrli, OS)
     C++	extern "OS" { int DSNRLI( char * functn, ...); }
     PL/I	DCL DSNRLI ENTRY OPTIONS(ASM,INTER,RETCODE);

   • Implicitly invoke RRSAF by including SQL statements or IFI calls in your program just as you would in any program. The RRSAF facility establishes the connection to Db2 with the default values for the subsystem name, plan name and authorization ID.
     Restriction: If your program can make its first SQL call from different modules with different DBRMs, you cannot use a default plan name and thus, you cannot implicitly invoke RRSAF. Instead, you must explicitly invoke RRSAF by calling the CREATE THREAD function.
     Requirement: If your application includes both SQL and IFI calls, you must issue at least one SQL call before you issue any IFI calls. This action ensures that your application uses the correct plan.
2. If you implicitly invoked RRSAF, determine if the implicit connection was successful by examining the return code and reason code immediately after the first executable SQL statement within the application program. Your program can check these codes by performing one of the following actions:
   • Examine registers 0 and 15 directly.
   • Examine the SQLCA, and if the SQLCODE is -981, obtain the return and reason code from the message text. The return code is the first token, and the reason code is the second token.

   If the implicit connection is successful, the application can examine the SQLCODE for the first, and subsequent, SQL statements.

Example of an RRSAF configuration

The following figure shows an conceptual example of invoking and using RRSAF.