qemu/include/qapi
Markus Armbruster 8277d2aa58 error: New error_prepend(), error_reportf_err()
Instead of simply propagating an error verbatim, we sometimes want to
add to its message, like this:

    frobnicate(arg, &err);
    error_setg(errp, "Can't frobnicate %s: %s",
                     arg, error_get_pretty(err));
    error_free(err);

This is suboptimal, because it loses err's hint (if any).  Moreover,
when errp is &error_abort or is subsequently propagated to
&error_abort, the abort message points to the place where we last
added to the error, not to the place where it originated.

To avoid these issues, provide means to add to an error's message in
place:

    frobnicate(arg, errp);
    error_prepend(errp, "Can't frobnicate %s: ", arg);

Likewise, reporting an error like

    frobnicate(arg, &err);
    error_report("Can't frobnicate %s: %s", arg, error_get_pretty(err));

can lose err's hint.  To avoid:

    error_reportf_err(err, "Can't frobnicate %s: ", arg);

The next commits will put these functions to use.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1450452927-8346-10-git-send-email-armbru@redhat.com>
2016-01-13 15:16:17 +01:00
..
qmp qapi: Convert QType into QAPI built-in enum type 2015-12-17 08:21:28 +01:00
dealloc-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
error.h error: New error_prepend(), error_reportf_err() 2016-01-13 15:16:17 +01:00
opts-visitor.h OptsVisitor: don't try to flatten overlong integer ranges 2013-08-20 11:52:00 -04:00
qmp-event.h qapi: add event helper functions 2014-06-23 11:01:25 -04:00
qmp-input-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
qmp-output-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
string-input-visitor.h qapi: move include files to include/qobject/ 2012-12-19 08:31:31 +01:00
string-output-visitor.h qapi: Add human mode to StringOutputVisitor 2014-02-14 21:12:03 +01:00
util.h qom: Make enum string tables const-correct 2015-06-19 18:42:18 +02:00
visitor-impl.h qapi: Simplify visits of optional fields 2015-12-17 08:21:29 +01:00
visitor.h qapi: Shorter visits of optional fields 2015-12-17 08:21:29 +01:00