[PATCH kvmtool v2 1/4] util: Make pr_err() return void

[Alexandru Elisei <alexandru.elisei@xxxxxxx>]

Of all the pr_* functions, pr_err() is the only function that returns a
value, which is -1. The code in parse_options is the only code that relies
on pr_err() returning a value, and that value must be exactly -1, because
it is being treated differently than the other return values.

This makes the code opaque, because it's not immediately obvious where that
value comes from, and fragile, as a change in the return value of pr_err
would break it.

Make pr_err() more like the other functions and don't return a value.

Reviewed-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
Signed-off-by: Alexandru Elisei <alexandru.elisei@xxxxxxx>
---
Changelog:

- Added Reviewed-by from Jean-Philippe, thanks!
- Remove unneeded " " in get_arg()

 include/kvm/util.h   |  2 +-
 util/parse-options.c | 28 ++++++++++++++++------------
 util/util.c          |  3 +--
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/include/kvm/util.h b/include/kvm/util.h
index b49454876a83..f51f370d2b37 100644
--- a/include/kvm/util.h
+++ b/include/kvm/util.h
@@ -39,7 +39,7 @@ extern bool do_debug_print;
 
 extern void die(const char *err, ...) NORETURN __attribute__((format (printf, 1, 2)));
 extern void die_perror(const char *s) NORETURN;
-extern int pr_err(const char *err, ...) __attribute__((format (printf, 1, 2)));
+extern void pr_err(const char *err, ...) __attribute__((format (printf, 1, 2)));
 extern void pr_warning(const char *err, ...) __attribute__((format (printf, 1, 2)));
 extern void pr_info(const char *err, ...) __attribute__((format (printf, 1, 2)));
 extern void set_die_routine(void (*routine)(const char *err, va_list params) NORETURN);
diff --git a/util/parse-options.c b/util/parse-options.c
index 9a1bbee6c271..d353256e2651 100644
--- a/util/parse-options.c
+++ b/util/parse-options.c
@@ -17,10 +17,13 @@
 static int opterror(const struct option *opt, const char *reason, int flags)
 {
 	if (flags & OPT_SHORT)
-		return pr_err("switch `%c' %s", opt->short_name, reason);
-	if (flags & OPT_UNSET)
-		return pr_err("option `no-%s' %s", opt->long_name, reason);
-	return pr_err("option `%s' %s", opt->long_name, reason);
+		pr_err("switch `%c' %s", opt->short_name, reason);
+	else if (flags & OPT_UNSET)
+		pr_err("option `no-%s' %s", opt->long_name, reason);
+	else
+		pr_err("option `%s' %s", opt->long_name, reason);
+
+	return -1;
 }
 
 static int get_arg(struct parse_opt_ctx_t *p, const struct option *opt,
@@ -429,14 +432,15 @@ is_abbreviated:
 		return get_value(p, options, flags);
 	}
 
-	if (ambiguous_option)
-		return pr_err("Ambiguous option: %s "
-				"(could be --%s%s or --%s%s)",
-				arg,
-				(ambiguous_flags & OPT_UNSET) ?  "no-" : "",
-				ambiguous_option->long_name,
-				(abbrev_flags & OPT_UNSET) ?  "no-" : "",
-				abbrev_option->long_name);
+	if (ambiguous_option) {
+		pr_err("Ambiguous option: %s (could be --%s%s or --%s%s)",
+			arg,
+			(ambiguous_flags & OPT_UNSET) ?  "no-" : "",
+			ambiguous_option->long_name,
+			(abbrev_flags & OPT_UNSET) ?  "no-" : "",
+			abbrev_option->long_name);
+		return -1;
+	}
 	if (abbrev_option)
 		return get_value(p, abbrev_option, abbrev_flags);
 	return -2;
diff --git a/util/util.c b/util/util.c
index 1877105e3c08..f59f26e1581c 100644
--- a/util/util.c
+++ b/util/util.c
@@ -47,14 +47,13 @@ void die(const char *err, ...)
 	va_end(params);
 }
 
-int pr_err(const char *err, ...)
+void pr_err(const char *err, ...)
 {
 	va_list params;
 
 	va_start(params, err);
 	error_builtin(err, params);
 	va_end(params);
-	return -1;
 }
 
 void pr_warning(const char *warn, ...)
-- 
2.41.0