mdb_openfd() and mdb_closefd() Functions

void *mdb_openfd(const char *path, int flag, mode_t mode);
void mdb_closefd(void * handle);

The mdb_openfd() function takes the identical arguments as the open() system call. It opens the specified file and registers a callback to close the file descriptor if it has not been closed already. mdb_openfd() returns an opaque token that can be passed to the mdb_preadfd() and mdb_pwritefd() functions.

The mdb_close() function closes the file descriptor for the specified file.