The describe_column_get v4 API method is used by the table UDF to retrieve properties about an individual column of a TABLE parameter.
a_sql_int32 (SQL_CALLBACK *describe_column_get)(
a_v4_extfn_proc_context *cntxt,
a_sql_uint32 arg_num,
a_sql_uint32 column_num,
a_v4_extfn_describe_parm_type describe_type,
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 retrieve. |
| describe_buffer | A structure that holds the describe information for the specified property to get from 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.