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, 4 insertions, 4 deletions

diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index ce43c02..00d069b 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -30,10 +30,10 @@ void loc_set_none(void);
 void loc_set_cmdline(char **argv, int idx, int cnt);
 void loc_set_file(const char *fname, int lno);
 
-void error_vprintf(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
-void error_printf(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
-void error_vprintf_unless_qmp(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
-void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
+int error_vprintf(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
+int error_printf(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
+int error_vprintf_unless_qmp(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
+int error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
 
 void error_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
 void warn_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);