r1ccard0
asked on
select and FD_ISSET problem
I have two processes running A,B. I send B a message from A, which it receiveds, but when FD_ISSET checks the sock descriptor if more data is there, it states yes. when my code trys a read the result is nothing.
The problem is why does FD_ISSET still think data is there.
The buffer is large enought to hold the data, and the message is received correctly and succesfully.
An attempt to FD_CLR() does not clear the sock des.
I'm, using SunOS 4.1. Unix, not Linux.
Why does the same thing happen when I create and close a socket ?
The problem is why does FD_ISSET still think data is there.
The buffer is large enought to hold the data, and the message is received correctly and succesfully.
An attempt to FD_CLR() does not clear the sock des.
I'm, using SunOS 4.1. Unix, not Linux.
Why does the same thing happen when I create and close a socket ?
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ASKER
points waarded to julio
int myfd;
fd_set readfds;
struct timeval timeval;
int ready;
Before EVERY read you must have the following sequence:
FD_ZERO(readfds);
FD_SET(myfd, &readfds);
/* either */
timeval.tv_sec = seconds;
timeval.tv_usec = 0;
/* or NULL as the 5th argument to select() */
ready = select((myfd+1), &readfds, NULL, NULL, &timeval);
if (ready == -1)
{
if (errno == EINTR)
continue;
else
{ERROR}
}
else if (ready == 0)
{TIMEOUT}
if (FD_ISSET(myfd, &readfds))
{DO_THE_READ}
In other words you can only use FD_ISSET() after first using FD_ZERO() FS_SET() and select().