On 30 April 2013 21:49, Nala Ginrut <nalagin...@gmail.com> wrote: >> > 6. other helper functions also available: >> >> If you want a port, use a port. Likewise for strings, bytevectors. >> > > For an instance, in a multi-thread program, if we use port and need to > move the cursor, we have to remember/restore the cursor for other > threads. But if we use mmap, we don't have to do that, each thread keeps > their own pointer/index. > And why not read them all into a bytevector? Yes, it helps, but as I > explained, the very big file. >
After mmap you have a pointer. You can make any number of ports from that pointer, each thread can just have its own port if that behaviour is desired. The useful information from mmap is a pointer. There are already procedures in place to wrap other datatypes/interface around pointers, for example: (define ptr (mmap arg ...)) (define port (open-bytevector-input-port (pointer->bytevector ptr len))) No need to duplicate any of port, string, etc. interfaces. Regards
