The mi_char and mi_string data types are the DataBlade API equivalents of the char C-language data type. These two data types are exactly the same in both storage and functionality. Use them to declare character strings in your DataBlade API module.
You can use the mi_char or mi_string data type to hold CHAR or VARCHAR data, as long as this data is not an argument or return value of a C UDR. For more information, see Character Data in C UDRs (Server).
You can use the mi_char and mi_string data types to store multibyte characters (NCHAR and NVARCHAR columns). However, your code must track how many bytes each character contains. You can use the IBM Informix GLS interface to assist with this process. For more information on multibyte characters, see the IBM Informix: GLS User's Guide.
The mi_char and mi_string data types cannot fit into an MI_DATUM structure. They must be passed by reference within C UDRs.
All data types, including mi_char and mi_string, must be passed by reference within client LIBMI applications.