The name of the function in the C or C++ source code follows the C function naming conventions, with the additional restriction that the name cannot be longer than 30 characters.
In C++, the function definition must be preceded by extern "C" so that the function name is not converted to a C++ overloaded name. For example:
extern "C"
void f1( INTEGER *a, INTEGER *result, char sqlstate[6])
{
...
}
The function can call any module written in C++.
When you use the CREATE FUNCTION or REPLACE FUNCTION statement to install the UDF, you specify the name of the C or C++ function. For more information, see Specifying the C/C++ Function Name.
On a Linux system, long names can sometimes cause errors when you install a UDF. For more information, see Troubleshooting “Arg list too long” and “Argument list too long” Errors.
For information on how the name of the C or C++ function relates to UDF name overloading, see Function Name Overloading.