Can you explain the IoMethod and IoFile from the os.h ??? I see the follwing in the code... #if OS_UNIX #define sqlite3OsOpenReadWrite sqlite3UnixOpenReadWrite . #endif #if OS_WIN #define sqlite3OsOpenReadWrite sqlite3WinOpenReadWrite #if OS_OS2 #define sqlite3OsOpenReadWrite sqlite3Os2OpenReadWrite etc... followed by IoMethod and IoFile type and struct delcarations. I understand the the defines are used as subtitutions in the pre processor for calls. int sqlite3OsOpenReadWrite(const char*, OsFile**, int*); --- Really becomes an instance of one of the above specific calls such as : sqlite3UnixOpenReadWrite My questions is why are the pointers stored in IxMethod ??? Since really the ifdefs above define the various interfaces to the operating system specific calls. why keep reference pointers to the functions inside of IxMethod ??? I'm building an interface into os system calls such as open/fopen read/fread and i'd like to be able to have the calling code dynamically set up which interace to use, so I'm trying to get a handle on the above code as a roadmap... Thanks, Ken
