The describe_column_set v4 API method sets UDF column-level properties on the server.
a_sql_int32 (SQL_CALLBACK *describe_column_set)( a_v4_extfn_proc_context *cntxt, a_sql_uint32 arg_num, a_sql_uint32 column_num, a_v4_extfn_describe_udf_type describe_type, const void *describe_buffer, size_t describe_buffer_len );
| Parameter | Description |
|---|---|
| cntxt | The procedure context object for this UDF. |
| arg_num | The ordinal of the TABLE parameter (0 is the result table, 1 for first input argument). |
| column_num | The ordinal of the column starting at 1. |
| describe_type | A selector indicating what property to set. |
| describe_buffer | A structure that holds the describe information for the specified property to set on the server. The specific structure or data type is indicated by the describe_type parameter. |
| describe_buffer_length | The length, in bytes, of the describe_buffer. |
On success, returns the number of bytes written to the describe_buffer. If an error occurs, or no property is retrieved, this function returns one of the generic describe_column errors.