Improve documentation of 'network-lookup-address-info'

* src/process.c (Fnetwork_lookup_address_info):
* doc/lispref/processes.texi (Misc Network): Document the error
message emitted by 'network-lookup-address-info' when it fails.

2 files changed, 5 insertions, 3 deletions

diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 6970f718ee0..94818beb4c9 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -3082,7 +3082,8 @@ signaled. Call @code{puny-encode-domain} on @var{name}
 first if you wish to lookup internationalized hostnames.
 
 If successful it returns a list of Lisp representations of network
-addresses, otherwise it returns @code{nil}.
+addresses, otherwise it returns @code{nil}.  In the latter case, it
+also displays the error message hopefully explaining what went wrong.
 
 By default both IPv4 and IPv6 lookups are attempted.  The optional
 argument @var{family} controls this behavior, specifying the symbol
diff --git a/src/process.c b/src/process.c
index 91d426103d8..27808848972 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4664,12 +4664,13 @@ network_lookup_address_info_1 (Lisp_Object host, const char *service,
 
 DEFUN ("network-lookup-address-info", Fnetwork_lookup_address_info,
        Snetwork_lookup_address_info, 1, 2, 0,
-       doc: /* Look up ip address info of NAME.
+       doc: /* Look up Internet Protocol (IP) address info of NAME.
 Optional parameter FAMILY controls whether to look up IPv4 or IPv6
 addresses.  The default of nil means both, symbol `ipv4' means IPv4
 only, symbol `ipv6' means IPv6 only.  Returns a list of addresses, or
 nil if none were found.  Each address is a vector of integers, as per
-the description of ADDRESS in `make-network-process'.  */)
+the description of ADDRESS in `make-network-process'.  In case of
+error displays the error message.  */)
      (Lisp_Object name, Lisp_Object family)
 {
   Lisp_Object addresses = Qnil;