diff --git a/Lib/distutils/ccompiler.py b/Lib/distutils/ccompiler.py
index 88a910c6810..3a7b5b84e1a 100644
--- a/Lib/distutils/ccompiler.py
+++ b/Lib/distutils/ccompiler.py
@@ -748,8 +748,9 @@ class CCompiler:
             for incl in includes:
                 f.write("""#include "%s"\n""" % incl)
             f.write("""\
-main (int argc, char **argv) {
+int main (int argc, char **argv) {
     %s();
+    return 0;
 }
 """ % funcname)
         finally:
diff --git a/Misc/NEWS.d/next/Library/2019-08-28-14-04-18.bpo-37965.7xGE-C.rst b/Misc/NEWS.d/next/Library/2019-08-28-14-04-18.bpo-37965.7xGE-C.rst
new file mode 100644
index 00000000000..116a9e49dcc
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-08-28-14-04-18.bpo-37965.7xGE-C.rst
@@ -0,0 +1 @@
+Fix C compiler warning caused by distutils.ccompiler.CCompiler.has_function.