Test for (fd < 0) before trying to FD_SET it

diff --git a/rts/posix/Select.c b/rts/posix/Select.c
index d36e122..932fc79 100644 (file)
--- a/rts/posix/Select.c
+++ b/rts/posix/Select.c
@@ -156,7 +156,7 @@ awaitEvent(rtsBool wait)
        case BlockedOnRead:
          { 
            int fd = tso->block_info.fd;
-           if (fd >= (int)FD_SETSIZE) {
+           if ((fd >= (int)FD_SETSIZE) || (fd < 0)) {
                barf("awaitEvent: descriptor out of range");
            }
            maxfd = (fd > maxfd) ? fd : maxfd;
@@ -167,7 +167,7 @@ awaitEvent(rtsBool wait)
        case BlockedOnWrite:
          { 
            int fd = tso->block_info.fd;
-           if (fd >= (int)FD_SETSIZE) {
+           if ((fd >= (int)FD_SETSIZE) || (fd < 0)) {
                barf("awaitEvent: descriptor out of range");
            }
            maxfd = (fd > maxfd) ? fd : maxfd;