BOOL openDBFfile(cdbfapiPlus* handle, char *filename);

This function opens DBF file. It accepts a string and returns a boolean value, true if everything was good.
Do not forget to close your file if you do not need it anymore.

{
    cdbfapiPlus* dbf = cdbfapiCreate();
    if (!dbf) return;
    
    if (openDBFFile(dbf, "c:\\tmp\\example.dbf"))
    {
        // your code
        closeDBFFile(dbf);
    }
    cdbfapiRelease(dbf);
}