If you are using the unixODBC Driver Manager, SQLDataSources (or DBI->data_sources
if you are using Perl) will return the data sources found in the odbc.ini file. However, if any of these data sources are missing the Driver attribute or have a Driver attribute for which there is no corresponding ODBC Driver in the odbcinst.ini file, unixODBC will return:
IM002, Data source name not found, and no default driver specified.
Note that if your application is linked directly with Easysoft ODBC-ODBC Bridge (no Driver Manager), it will use the SQLDataSources function in the ODBC-ODBC Bridge instead.