ODBC Tcl API and C API differences

The Tcl API is similar to the C API. One set of ODBC documentation can be used for both APIs, and existing ODBC C applications can be ported to Tcl. There are several generic differences between the C ODBC API and these Tcl extensions.

Handles in the C API are pointers to memory. Handles in Tcl are short strings ending in a number, such as environment handle henv0, connection handle hdbc0, statement handle hstmt0, and descriptor handle hdesc0.

Some instances in C have an object specified as input. In Tcl, specify a string value through a literal value or with a "$" preceding a variable name.

For instances in which the C argument is a pointer to an object, the corresponding Tcl argument is a variable name. In most cases the argument is an output argument.