From f4d0064afcff4c38b379800674938cde8f069dcd Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Fri, 18 Dec 2015 16:35:08 +0100 Subject: error: Improve documentation While there, tighten error_append_hint()'s assertion. Signed-off-by: Markus Armbruster Message-Id: <1450452927-8346-6-git-send-email-armbru@redhat.com> Reviewed-by: Eric Blake --- include/qapi/error.h | 20 ++++++++++++++++++-- util/error.c | 2 +- util/qemu-error.c | 8 ++++---- 3 files changed, 23 insertions(+), 7 deletions(-) diff --git a/include/qapi/error.h b/include/qapi/error.h index 1480f59ec5..b18a608c6d 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -18,6 +18,15 @@ * Create an error: * error_setg(&err, "situation normal, all fouled up"); * + * Create an error and add additional explanation: + * error_setg(&err, "invalid quark"); + * error_append_hint(&err, "Valid quarks are up, down, strange, " + * "charm, top, bottom.\n"); + * + * Do *not* contract this to + * error_setg(&err, "invalid quark\n" + * "Valid quarks are up, down, strange, charm, top, bottom."); + * * Report an error to stderr: * error_report_err(err); * This frees the error object. @@ -26,6 +35,7 @@ * const char *msg = error_get_pretty(err); * do with msg what needs to be done... * error_free(err); + * Note that this loses hints added with error_append_hint(). * * Handle an error without reporting it (just for completeness): * error_free(err); @@ -142,6 +152,8 @@ ErrorClass error_get_class(const Error *err); * If @errp is anything else, *@errp must be NULL. * The new error's class is ERROR_CLASS_GENERIC_ERROR, and its * human-readable error message is made from printf-style @fmt, ... + * The resulting message should be a single phrase, with no newline or + * trailing punctuation. */ #define error_setg(errp, fmt, ...) \ error_setg_internal((errp), __FILE__, __LINE__, __func__, \ @@ -198,7 +210,11 @@ void error_propagate(Error **dst_errp, Error *local_err); /** * Append a printf-style human-readable explanation to an existing error. - * May be called multiple times, and safe if @errp is NULL. + * @errp may be NULL, but not &error_fatal or &error_abort. + * Trivially the case if you call it only after error_setg() or + * error_propagate(). + * May be called multiple times. The resulting hint should end with a + * newline. */ void error_append_hint(Error **errp, const char *fmt, ...) GCC_FMT_ATTR(2, 3); @@ -232,7 +248,7 @@ void error_free_or_abort(Error **errp); /* * Convenience function to error_report() and free @err. */ -void error_report_err(Error *); +void error_report_err(Error *err); /* * Just like error_setg(), except you get to specify the error class. diff --git a/util/error.c b/util/error.c index 9b27c4508e..ebfb74b02e 100644 --- a/util/error.c +++ b/util/error.c @@ -132,7 +132,7 @@ void error_append_hint(Error **errp, const char *fmt, ...) return; } err = *errp; - assert(err && errp != &error_abort); + assert(err && errp != &error_abort && errp != &error_fatal); if (!err->hint) { err->hint = g_string_new(NULL); diff --git a/util/qemu-error.c b/util/qemu-error.c index c1574bb348..ecf5708478 100644 --- a/util/qemu-error.c +++ b/util/qemu-error.c @@ -200,8 +200,8 @@ static void error_print_loc(void) bool enable_timestamp_msg; /* * Print an error message to current monitor if we have one, else to stderr. - * Format arguments like vsprintf(). The result should not contain - * newlines. + * Format arguments like vsprintf(). The resulting message should be + * a single phrase, with no newline or trailing punctuation. * Prepend the current location and append a newline. * It's wrong to call this in a QMP monitor. Use error_setg() there. */ @@ -224,8 +224,8 @@ void error_vreport(const char *fmt, va_list ap) /* * Print an error message to current monitor if we have one, else to stderr. - * Format arguments like sprintf(). The result should not contain - * newlines. + * Format arguments like sprintf(). The resulting message should be a + * single phrase, with no newline or trailing punctuation. * Prepend the current location and append a newline. * It's wrong to call this in a QMP monitor. Use error_setg() there. */ -- cgit v1.2.1