[lib] Add comments regarding setsockopt_multicast_ipv4 arguments.

2007-07-06 Andrew J. Schorr <ajschorr@alumni.princeton.edu>

	* sockopt.{c,h}: (setsockopt_multicast_ipv4) Add some comments about
	  the arguments.

diff --git a/lib/ChangeLog b/lib/ChangeLog
index 3a1d1f6ba0c0429d4393f390e5d4ffb82d04fa56..2d8e5deb823224b30f6b24dc996252d789f59690 100644 (file)
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,8 @@
+2007-07-06 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
+       * sockopt.{c,h}: (setsockopt_multicast_ipv4) Add some comments about
+         the arguments.
+
 2007-06-01 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
 
        * zebra.h: On linux, we seem to need to include <linux/types.h> before

diff --git a/lib/sockopt.c b/lib/sockopt.c
index 6ddbded132c5430f9e5c6566cbf210f115408555..f5f1a7edd8d182cf334fd5993f0c32b5af3c6b58 100644 (file)
--- a/lib/sockopt.c
+++ b/lib/sockopt.c
@@ -176,9 +176,10 @@ getsockopt_ipv6_ifindex (struct msghdr *msgh)
 int
 setsockopt_multicast_ipv4(int sock, 
                        int optname, 
-                       struct in_addr if_addr,
+                       struct in_addr if_addr /* required */,
                        unsigned int mcast_addr,
-                       unsigned int ifindex)
+                       unsigned int ifindex /* optional: if non-zero, may be
+                                                 used instead of if_addr */)
 {
 
 #ifdef HAVE_STRUCT_IP_MREQN_IMR_IFINDEX

diff --git a/lib/sockopt.h b/lib/sockopt.h
index d88bfa6d670bf08a369aca5fedc484bfab0f701b..65ba34f1bafad9674b47126fa672b2da2225dad8 100644 (file)
--- a/lib/sockopt.h
+++ b/lib/sockopt.h
@@ -79,9 +79,12 @@ extern int setsockopt_ipv6_multicast_loop (int, int);
                     ? SOPT_SIZE_CMSG_PKTINFO_IPV6())
 
 extern int setsockopt_multicast_ipv4(int sock, int optname, 
-                                    struct in_addr if_addr,
+                                    struct in_addr if_addr
+                                        /* required: interface to join on */,
                                      unsigned int mcast_addr,
-                                    unsigned int ifindex);
+                                    unsigned int ifindex
+                                        /* optional: if non-zero, may be used
+                                               instead of if_addr */);
 
 /* Ask for, and get, ifindex, by whatever method is supported. */
 extern int setsockopt_ifindex (int, int, int);