From 906766f590c1ea4db083fdf799ae48595198914c Mon Sep 17 00:00:00 2001 From: Alejandro Colomar Date: Sun, 25 Oct 2020 00:21:16 +0200 Subject: [PATCH] stailq.3: Add remaining details to complete the page Signed-off-by: Alejandro Colomar Signed-off-by: Michael Kerrisk --- man3/stailq.3 | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/man3/stailq.3 b/man3/stailq.3 index 0abacd824..2896d27c9 100644 --- a/man3/stailq.3 +++ b/man3/stailq.3 @@ -51,6 +51,7 @@ STAILQ_REMOVE, .\"STAILQ_REMOVE_AFTER, STAILQ_REMOVE_HEAD, .\"STAILQ_SWAP +\- implementation of a singly-linked tail queue .SH SYNOPSIS .nf .B #include @@ -100,6 +101,8 @@ STAILQ_REMOVE_HEAD, .\" .BI " STAILQ_ENTRY " NAME ");" .fi .SH DESCRIPTION +These macros define and operate on singly-linked tail queues. +.PP In the macro definitions, .I TYPE is the name of a user-defined structure, @@ -292,11 +295,38 @@ from the tail queue. .\" and .\" .IR head2 . .SH RETURN VALUE +.BR STAILQ_EMPTY () +returns nonzero if the queue is empty, +and zero if the queue contains at least one entry. +.PP +.BR STAILQ_FIRST (), +and +.BR STAILQ_NEXT () +return a pointer to the first or next +.I STAILQ_ENTRY +structure, respectively. +.PP +.BR STAILQ_HEAD_INITIALIZER () +returns an initializer that can be assigned to the queue +.IR head . .SH CONFORMING TO Not in POSIX.1, POSIX.1-2001 or POSIX.1-2008. Present on the BSDs (STAILQ macros first appeared in 4.4BSD). .SH BUGS +The macro +.BR STAILQ_FOREACH () +doesn't allow +.I var +to be removed or freed within the loop, +as it would interfere with the traversal. +The macro +.BR STAILQ_FOREACH_SAFE (), +which is present on the BSDs but is not present in glibc, +fixes this limitation by allowing +.I var +to safely be removed from the list and freed from within the loop +without interfering with the traversal. .SH EXAMPLES .EX #include