Add adns support in background resolver.

[mLib] / man / bres.3

diff --git a/man/bres.3 b/man/bres.3
index 9552656df42e867814304bc3152249f7a41b2f65..f6f790bedad6215643acf1fc4066e0a1429eee30 100644 (file)
--- a/man/bres.3
+++ b/man/bres.3
@@ -85,12 +85,14 @@ The function
 cancels a running resolver job.  When it returns, the client structure
 is safe to discard.
 .PP
-The resolver is currently implemented using a pool of server processes.
-Incoming resolver jobs are passed to an available server, or a new
-server is started if all are busy.  There is a maximum number of
-servers, and jobs are queued once this limit is reached.  Old servers
-which have been idle for a period of time are killed off.  Servers are
-also killed if they start misbehaving or their jobs are aborted.
+There are two versions of 
+.BR bres .
+The standard one uses a pool of server processes.  Incoming resolver
+jobs are passed to an available server, or a new server is started if
+all are busy.  There is a maximum number of servers, and jobs are queued
+once this limit is reached.  Old servers which have been idle for a
+period of time are killed off.  Servers are also killed if they start
+misbehaving or their jobs are aborted.
 .PP
 By default, servers are started simply by calling
 .BR fork (2).
@@ -105,6 +107,18 @@ memory consumption.  The argument to
 is the full pathname of the server program, or null to accept the
 default set at library configuration time (which is usually correct).
 .PP
+The other implementation of
+.B bres
+uses the
+.B adns
+library to do asynchronous resolution.  It can cope with many more
+simultaneous resolver jobs, and doesn't use up external processes.  If
+you're using the
+.BR adns -based
+resolver, then the
+.B bres_exec
+function does nothing at all.
+.PP
 For security reasons, when an address is resolved, the hostname received
 is verified by performing a forward lookup.  If the forward lookup fails
 to return the expected IP address, an error is reported.