monitor error: Make printf()-like functions return a value

printf() & friends return the number of characters written on success,
negative value on error.

monitor_printf(), monitor_vfprintf(), monitor_vprintf(),
error_printf(), error_printf_unless_qmp(), error_vprintf(), and
error_vprintf_unless_qmp() return void.  Some of them carry a TODO
comment asking for int instead.

Improve them to return int like printf() does.

This makes our use of monitor_printf() as fprintf_function slightly
less dirty: the function cast no longer adds a return value that isn't
there.  It still changes a parameter's pointer type.  That will be
addressed in a future commit.

monitor_vfprintf() always returns zero.  Improve it to return the
proper value.

Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190417190641.26814-11-armbru@redhat.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/util/qemu-error.c b/util/qemu-error.c
index d08139d9ac..f373f3b3b0 100644
--- a/util/qemu-error.c
+++ b/util/qemu-error.c
@@ -24,22 +24,26 @@ typedef enum {
     REPORT_TYPE_INFO,
 } report_type;
 
-void error_printf(const char *fmt, ...)
+int error_printf(const char *fmt, ...)
 {
     va_list ap;
+    int ret;
 
     va_start(ap, fmt);
-    error_vprintf(fmt, ap);
+    ret = error_vprintf(fmt, ap);
     va_end(ap);
+    return ret;
 }
 
-void error_printf_unless_qmp(const char *fmt, ...)
+int error_printf_unless_qmp(const char *fmt, ...)
 {
     va_list ap;
+    int ret;
 
     va_start(ap, fmt);
-    error_vprintf_unless_qmp(fmt, ap);
+    ret = error_vprintf_unless_qmp(fmt, ap);
     va_end(ap);
+    return ret;
 }
 
 static Location std_loc = {