C and C++ routines

C and C++ routines are external routines that are created by executing a CREATE PROCEDURE, CREATE FUNCTION, or CREATE METHOD statement that references a library built from C or C++ source code as its external code body.

C and C++ routines can optionally execute SQL statements by including embedded SQL statements.

The following terms are important in the context of C and C++ routines:
CREATE statement
The SQL language CREATE statement used to create the routine in the database.
Routine-body source code
The source code file containing the C or C++ routine implementation that corresponds to the CREATE statement EXTERNAL clause specification.
The database utility that pre-parses the routine source code implementation to validate SQL statements contained in the code and generates a package.
The programming language specific software required to compile and link the source code implementation.
The file containing the runtime access path information that the database manager uses at routine runtime to execute the SQL statements contained in the routine code implementation.
Routine library
A file that contains the compiled form of the routine source code.
Before developing a C or C++ routine, it is important to both understand the basics of routines and the unique features and characteristics specific to C and C++ routines. An understanding of the Embedded SQL API and the basics of embedded SQL application development is also important. To learn more about these subjects, refer to the following topics:
  • External routines
  • Embedded SQL
  • Include files for C and C++ routines
  • Parameters in C and C++ routines
  • Restrictions on C and C++ routines
Developing a C or C++ routines involves following a series of step by step instructions and looking at C or C++ routine examples. Refer to:
  • Creating C and C++ routines
  • Examples of C procedures
  • Examples of C user-defined functions