.\"SLIST_REMOVE_AFTER,
SLIST_REMOVE_HEAD
.\"SLIST_SWAP
+\- implementation of a singly-linked list
.SH SYNOPSIS
.nf
.B #include <sys/queue.h>
.\".BI "void SLIST_SWAP(SLIST_HEAD *" head1 ", SLIST_HEAD *" head2 ", SLIST_ENTRY " NAME ");"
.fi
.SH DESCRIPTION
+These macros define and operate on doubly-linked lists.
+.PP
In the macro definitions,
.I TYPE
is the name of a user-defined structure,
.\" and
.\" .IR head2 .
.SH RETURN VALUE
+.BR SLIST_EMPTY ()
+returns non-zero if the list is empty,
+and zero if the list contains at least one entry.
+.PP
+.BR SLIST_FIRST (),
+and
+.BR SLIST_NEXT ()
+return a pointer to the first or next
+.I SLIST_ENTRY
+structure, respectively.
+.PP
+.BR SLIST_HEAD_INITIALIZER ()
+returns an initializer that can be assigned to the list
+.IR head .
.SH CONFORMING TO
Not in POSIX.1, POSIX.1-2001 or POSIX.1-2008.
Present on the BSDs
(SLIST macros first appeared in 4.4BSD).
.SH BUGS
+The macro
+.BR SLIST_FOREACH ()
+doesn't allow
+.I var
+to be removed or freed within the loop,
+as it would interfere with the traversal.
+The macro
+.BR SLIST_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 <stddef.h>
}
.EE
.SH SEE ALSO
+.BR insque (3),
+.BR queue (3)