The name of the method 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 get_area( UDT_HANDLE *circleUDT, FLOAT *result, char sqlstate[6])
{
...
}
The function can call any module written in C++.
When you use the CREATE METHOD statement to install the UDM, you specify the name of the C or C++ function. For more information, see "Specifying the C/C++ Function Name" in Installing the UDM.
On Linux, long names can sometimes cause errors when you install a UDM. For more information, see Argument list too long.