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MySQL 8.0 C API Developer Guide  /  C API Function Descriptions  /  mysql_fetch_field_direct()

7.19 mysql_fetch_field_direct()

MYSQL_FIELD *
mysql_fetch_field_direct(MYSQL_RES *result,
                         unsigned int fieldnr)

Description

Given a field number fieldnr for a column within a result set, returns that column's field definition as a MYSQL_FIELD structure. Use this function to retrieve the definition for an arbitrary column. Specify a value for fieldnr in the range from 0 to mysql_num_fields(result)-1.

For metadata-optional connections, this function returns NULL when the resultset_metadata system variable is set to NONE. To check whether a result set has metadata, use the mysql_result_metadata() function. For details about managing result set metadata transfer, see Chapter 27, C API Optional Result Set Metadata.

Return Values

The MYSQL_FIELD structure for the specified column. NULL if the result set has no metadata.

Errors

None.

Example

unsigned int num_fields;
unsigned int i;
MYSQL_FIELD *field;

num_fields = mysql_num_fields(result);
for(i = 0; i < num_fields; i++)
{
    field = mysql_fetch_field_direct(result, i);
    printf("Field %u is %s\n", i, field->name);
}