From 47ff5ac81e8bb3096500de7b132051691d533d36 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Tue, 7 Jul 2020 18:05:29 +0200 Subject: [PATCH] error: Fix examples in error.h's big comment Mark a bad example more clearly. Fix the error_propagate_prepend() example. Add a missing declaration and a second error pileup example. Signed-off-by: Markus Armbruster Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Greg Kurz Message-Id: <20200707160613.848843-2-armbru@redhat.com> --- include/qapi/error.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/include/qapi/error.h b/include/qapi/error.h index ad5b6e896d..e8960eaad5 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -24,7 +24,7 @@ * "charm, top, bottom.\n"); * * Do *not* contract this to - * error_setg(&err, "invalid quark\n" + * error_setg(&err, "invalid quark\n" // WRONG! * "Valid quarks are up, down, strange, charm, top, bottom."); * * Report an error to the current monitor if we have one, else stderr: @@ -52,7 +52,8 @@ * where Error **errp is a parameter, by convention the last one. * * Pass an existing error to the caller with the message modified: - * error_propagate_prepend(errp, err); + * error_propagate_prepend(errp, err, + * "Could not frobnicate '%s': ", name); * * Avoid * error_propagate(errp, err); @@ -108,12 +109,23 @@ * } * * Do *not* "optimize" this to + * Error *err = NULL; * foo(arg, &err); * bar(arg, &err); // WRONG! * if (err) { * handle the error... * } * because this may pass a non-null err to bar(). + * + * Likewise, do *not* + * Error *err = NULL; + * if (cond1) { + * error_setg(&err, ...); + * } + * if (cond2) { + * error_setg(&err, ...); // WRONG! + * } + * because this may pass a non-null err to error_setg(). */ #ifndef ERROR_H -- 2.11.0