diff options
| -rw-r--r-- | libc/misc/search/insremque.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/libc/misc/search/insremque.c b/libc/misc/search/insremque.c index c4a75ab89..99399427e 100644 --- a/libc/misc/search/insremque.c +++ b/libc/misc/search/insremque.c @@ -26,12 +26,20 @@ void insque (void *elem, void *prev) { - struct qelem *next = ((struct qelem *) prev)->q_forw; - ((struct qelem *) prev)->q_forw = (struct qelem *) elem; - if (next != NULL) - next->q_back = (struct qelem *) elem; - ((struct qelem *) elem)->q_forw = next; - ((struct qelem *) elem)->q_back = (struct qelem *) prev; + if (prev == NULL) + { + ((struct qelem *) elem)->q_forw = NULL; + ((struct qelem *) elem)->q_back = NULL; + } + else + { + struct qelem *next = ((struct qelem *) prev)->q_forw; + ((struct qelem *) prev)->q_forw = (struct qelem *) elem; + if (next != NULL) + next->q_back = (struct qelem *) elem; + ((struct qelem *) elem)->q_forw = next; + ((struct qelem *) elem)->q_back = (struct qelem *) prev; + } } #endif |