>Would someone please write me a code snippet which shows the proper
>usage of the select function when used to wait for data to be sent to a fifo
>from kernel-space.
Here you are:
fd_set rfds;
int fd_control,fd_data,fd_error;
if ((fd_data = open(RT_FIFO_DATA, O_RDONLY)) < 0) {
fprintf(stderr, "Error opening " RT_FIFO_DATA "\n");
exit(1);
}
if ((fd_error = open(RT_FIFO_ERROR, O_RDONLY)) < 0) {
fprintf(stderr, "Error opening " RT_FIFO_ERROR "\n");
exit(1);
}
/* Wait for data showing up in either fd_data or fd_error
no time-outs. For time-outs look at the according manpage
man 2 select */
FD_ZERO(&rfds);
FD_SET(fd_data, &rfds);
FD_SET(fd_error, &rfds);
select(FD_SETSIZE, &rfds, NULL, NULL, NULL);
if (FD_ISSET(fd_data, &rfds)) { // got data from in fd_data
...
}
if (FD_ISSET(fd_error, &rfds)) { // got data from in fd_error
...
}
>Does select to a busy-wait?
No.
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