Hi
I think the wording in ip(7) regarding how to set an address based on
INADDR_ANY or the return value of inet_aton(3) is misleading.
sin_addr is the IP host address. The s_addr member of struct in_addr
contains the host interface address in network byte order. in_addr
should be assigned one of the INADDR_* values (e.g., INADDR_ANY) or set
using the inet_aton(3), inet_addr(3), inet_makeaddr(3) library func-
tions or directly with the name resolver (see gethostbyname(3)).
The way I read it, it suggests I can do:
struct sockaddr_in sin;
sin.sin_addr = INADDR_ANY;
but I have to do:
struct sockaddr_in sin;
sin.sin_addr.s_addr = INADDR_ANY;
The key thing part is where it says "in_addr" where I would expect "s_addr".
Other suggestions:
- mention inet_makeaddr(3) separately from inet_aton(3) and inet_addr(3)
because they have different return types
- consider mentioning getaddrinfo(3) instead of gethostbyname(3) because
the latter is obsolete according to its own man page
Here's some suggested alternative wording:
sin_addr is the IP host address. The s_addr member of struct in_addr
contains the host interface address in network byte order. s_addr
should be assigned one of the INADDR_* values (e.g., INADDR_ANY) or set
using inet_aton(3) or inet_addr(3). Alternatively, sin_addr can be set
using inet_makeaddr(3), or sockaddr_in can be set using the structure
returned by getaddrinfo(3).
And a patch against git:
---
man7/ip.7 | 20 +++++++++++++-------
1 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/man7/ip.7 b/man7/ip.7
index 4561b2f..0399a24 100644
--- a/man7/ip.7
+++ b/man7/ip.7
@@ -150,17 +150,23 @@ The
member of
.I struct in_addr
contains the host interface address in network byte order.
-.I in_addr
+.I s_addr
should be assigned one of the
.BR INADDR_*
values (e.g.,
.BR INADDR_ANY )
-or set using the
-.BR inet_aton (3),
-.BR inet_addr (3),
-.BR inet_makeaddr (3)
-library functions or directly with the name resolver (see
-.BR gethostbyname (3)).
+or set using
+.BR inet_aton (3)
+or
+.BR inet_addr (3).
+Alternatively,
+.I sin_addr
+can be set using
+.BR inet_makeaddr (3),
+or
+.I sockaddr_in
+can be set using the structure returned by
+.BR getaddrinfo (3).
IPv4 addresses are divided into unicast, broadcast
and multicast addresses.
--
1.5.6.5
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