fix snprintf on output size 0

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/runner.py b/tests/runner.py
index f3289e46..deeb5689 100755
--- a/tests/runner.py
+++ b/tests/runner.py
@@ -4318,6 +4318,19 @@ at function.:blag
         '''
       self.do_run(src, re.sub('(^|\n)\s+', '\\1', expected))
 
+    def test_snprintf0(self):
+      src = r'''
+        #include <stdio.h>
+        int main()  {
+          int size = snprintf(NULL, 0, "%s %d %.2f\n", "me and myself", 25, 1.345);
+          char buf[size];
+          snprintf(buf, size, "%s %d %.2f\n", "me and myself", 25, 1.345);
+          printf("%d : %s\n", size, buf);
+          return 0;
+        }
+        '''
+      self.do_run(src, '22 : me and myself 25 1.34\n')
+
     def test_atoX(self):
       if self.emcc_args is None: return self.skip('requires ta2')