return code cleanup: build, init and run-time errors

Stop the abuse of CURLE_FAILED_INIT as return code for things not being
init related by introducing two new return codes:

CURLE_NOT_BUILT_IN and CURLE_UNKNOWN_OPTION

CURLE_NOT_BUILT_IN replaces return code 4 that has been obsoleted for
several years. It is used for returning error when something is
attempted to be used but the feature/option was not enabled or
explictitly disabled at build-time. Getting this error mostly means that
libcurl needs to be rebuilt.

CURLE_FAILED_INIT is now saved and used strictly for init
failures. Getting this problem means something went seriously wrong,
like a resource shortage or similar.

CURLE_UNKNOWN_OPTION is the option formerly known as
CURLE_UNKNOWN_TELNET_OPTION (and the old name is still present,
separately defined to be removed in a very distant future). This error
code is meant to be used to return when an option is given to libcurl
that isn't known. This problem would mostly indicate a problem in the
program that uses libcurl.

1 files changed, 13 insertions, 5 deletions

diff --git a/docs/libcurl/libcurl-errors.3 b/docs/libcurl/libcurl-errors.3
index c3c854e90..beabf98f0 100644
--- a/docs/libcurl/libcurl-errors.3
+++ b/docs/libcurl/libcurl-errors.3
@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2010, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -44,9 +44,15 @@ can be a misspelled protocol string or just a protocol libcurl has no code
 for.
 .IP "CURLE_FAILED_INIT (2)"
 Very early initialization code failed. This is likely to be an internal error
-or problem.
+or problem, or a resource problem where something fundamental couldn't get
+done at init time.
 .IP "CURLE_URL_MALFORMAT (3)"
 The URL was not properly formatted.
+.IP "CURLE_NOT_BUILT_IN (4)"
+A requested feature, protocol or option was not found built-in in this libcurl
+due to a build-time decision. This means that a feature or option was not
+enabled or explicitly disabled when libcurl was built and in order to get it
+to function you have to get a rebuilt libcurl.
 .IP "CURLE_COULDNT_RESOLVE_PROXY (5)"
 Couldn't resolve proxy. The given proxy host could not be resolved.
 .IP "CURLE_COULDNT_RESOLVE_HOST (6)"
@@ -145,9 +151,11 @@ CURLOPT_INTERFACE.
 .IP "CURLE_TOO_MANY_REDIRECTS (47)"
 Too many redirects. When following redirects, libcurl hit the maximum amount.
 Set your limit with CURLOPT_MAXREDIRS.
-.IP "CURLE_UNKNOWN_TELNET_OPTION (48)"
-An option set with CURLOPT_TELNETOPTIONS was not recognized/known. Refer to
-the appropriate documentation.
+.IP "CURLE_UNKNOWN_OPTION (48)"
+An option passed to libcurl is not recognized/known. Refer to the appropriate
+documentation. This is most likely a problem in the program that uses
+libcurl. The error buffer might contain more specific information about which
+exact option it concerns.
 .IP "CURLE_TELNET_OPTION_SYNTAX (49)"
 A telnet option string was Illegally formatted.
 .IP "CURLE_PEER_FAILED_VERIFICATION (51)"