MDAC 2.5 SDK - ODBC Programmer's Reference
Appendix D: Data Types

SQL to C: GUID

The identifier for the GUID ODBC SQL data type is:

SQL_GUID

The following table shows the ODBC C data types to which GUID SQL data may be converted. For an explanation of the columns and terms in the table, see "Converting Data from SQL to C Data Types."

C type identifier	Test	**TargetValuePtr*	*StrLen_or _IndPtr	SQLSTATE
SQL_C_CHAR	BufferLength > Character byte length	Data	36	n/a
	BufferLength < 37	Undefined	Undefined	22003
SQL_C_WCHAR	BufferLength > Character length	Data	36	n/a
	BufferLength < 37	Undefined	Undefined	22003
SQL_C_BINARY	Byte length of data <= BufferLength	Data	Length of data in bytes	n/a
	Byte length of data > BufferLength	Undefined	Undefined	22003
SQL_C_GUID	None^[a]	Data	16^[b]	n/a

[a] The value of BufferLength is ignored for this conversion. The driver assumes that the size of *TargetValuePtr is the size of the C data type.

[b] This is the size of the corresponding C data type.