Informix DataBlade API Programmer's Manual DataBlade API Function Descriptions

The mi_value() function retrieves a column value from a row, given the column identifier.

mi_integer mi_value(row, column_id, value_buf, value_len)

MI_ROW *row;

mi_integer column_id;

MI_DATUM *value_buf;

mi_integer *value_len;

row	is the row from which values are being extracted.
column_id	indicates the column identifier of the column, which specifies the position of the column in the specified row. Column numbering follows C programming conventions: the first column in the row is at position zero (0).
value_buf	is a pointer to an MI_DATUM structure that contains the column value. The mi_value() function allocates the MI_DATUM structure. You do not need to supply the buffer to hold the returned value.
value_len	is the length of the returned column value.

Valid in Client LIBMI Application?	Valid in User-Defined Routine?
Yes	Yes

The mi_value() function returns the value for the column that the column_id column identifier specifies. It retrieves this column value from the row structure that row references. This function is typically called in a loop that terminates when mi_value() has retrieved values for all the columns in the row.

Important: The "value_buf" parameter points to the representation of the value that corresponds to the control mode of the query: a character string for text representation and the internal format for binary representation.

The way to interpret the data returned in the value_buf depends on the mi_value() return value, as follows.

See the descriptions of the following functions: mi_collection_fetch(), mi_next_row(), mi_save_set_insert(), and mi_value_by_name().

For more information about how to retrieve values, see Obtaining Column Values.