errors resulting from setting named pipes to be non-blocking


Using C, I have been writing to named pipes in a non-blocking way and have been getting a whole bunch of EAGAIN errors. I have spent way too long on the web trying to find out why, and bumped onto this excellent answer. Looking at the manpage, I see that this would give the same value as EWOULDBLOCK, which is a far more meaningful name in this case.

This is what will display those errors:

if (write(fd, buffer, strlen(buffer)) == -1)
    fprintf (stderr, "error writing to file '%s': %s (errno %d)",
             path, strerror(errno), fd);

And here is how to avoid them:

if ((write(fd, buffer, strlen(buffer)) == -1) && (errno != EWOULDBLOCK)) {
    fprintf( stderr, "error writing to file '%s': %s (errno %d)",
             path, strerror(errno), fd);

To avoid this kind of confusion, I just wish these two variables did not refer to the same errno value.