From 393a5e9b24947f90cd116c4fb1b2ff4ee200f0df Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Fri, 8 Jan 2021 07:40:53 -0500 Subject: [PATCH 02/10] error: Fix examples in error.h's big comment MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Marc-André Lureau Message-id: <20210108074101.290008-3-marcandre.lureau@redhat.com> Patchwork-id: 100521 O-Subject: [RHEL-8.3.0.z qemu-kvm PATCH 02/10] error: Fix examples in error.h's big comment Bugzilla: 1913818 RH-Acked-by: Miroslav Rezanina RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Stefano Garzarella From: Marc-André Lureau From: Markus Armbruster 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> (cherry picked from commit 47ff5ac81e8bb3096500de7b132051691d533d36) Signed-off-by: Marc-André Lureau Signed-off-by: Danilo C. L. de Paula --- 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 3f95141a01a..83c38f9a188 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 -- 2.27.0