Hi Simon, Thanks for the confirmation. That makes things alot clear now.
Thanks again, Ambarish On Sun, Jul 3, 2011 at 3:54 PM, goldsi...@gmx.de <goldsi...@gmx.de> wrote: > ambarisha b wrote: > >> I am working on a OS independent port for lwip. I have a couple of issues >> with this. >> > Which version of lwIP are you using? I'm assuming 1.4.0 for the rest of > this mail. > > The function declarations for semaphores and mailboxes are different in >> sys_arch.txt and from lwip/sys.h. For example: >> >> sys_sem_t sys_sem_new(u8_t count); >> err_t sys_sem_new(sys_sem_t *sem, u8_t count); >> >> Why is this difference? Am I missing something here? >> > No, it's us that have been missing something: updating the docs. Theses > functions have been changed to take a pointer so that sys_sem_t can be > directly mapped to a preallocated OS-struct. Before this change > sys_sem_new() could only return a pointer to such a structure that had to be > allocated somewhere else. This should make OS ports both smaller and easier. > I'll update the docs in CVS. > > Another is that sys_mbox_post takes the pointer to the message. But the >> size of the message isn't passed. If the size of the message is passed in >> the buffer it self, it hasn't been documented. So, how does this work? >> > An mbox always contains 'void*' messages. The function that reads messages > from the mbox knows which type is allowed for this mbox and casts to the > correct type. If multiple messages are allowed in an mbox, we pass a struct > that contains type information. Since only pointers are passed through the > mbox, allocation/deallocation is taken care of outside the mbox > implementation. > > A couple of functions require that time spent waiting, be returned in >> milliseconds. How accurate should this be? What are the practical limits >> that you would suggest? >> > First, you never should return '0' if you waited, even if you spent far > less than a millisecond waiting. As to accuracy, that's difficult to say. It > should be as accurate as you can get it to, but just returning OS ticks here > (which are normally in a range of 1 to 20ms) should probably be good > enough... > > Simon > > _______________________________________________ > lwip-users mailing list > lwip-users@nongnu.org > https://lists.nongnu.org/mailman/listinfo/lwip-users >
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