Add a warning when we use in cdef() a global variable without also specifying a storage class (extern or static)

1 files changed, 8 insertions, 0 deletions

diff --git a/cffi/cparser.py b/cffi/cparser.py
index 9cb3412..c275f42 100644
--- a/cffi/cparser.py
+++ b/cffi/cparser.py
@@ -156,6 +156,13 @@ def _warn_for_string_literal(csource):
                           "confuse pre-parsing.")
             break
 
+def _warn_for_non_extern_non_static_global_variable(decl):
+    if not decl.storage:
+        import warnings
+        warnings.warn("Declaration of global variable '%s' in cdef() should "
+                      "be marked 'extern' for consistency (or possibly "
+                      "'static' in API mode)" % (decl.name,))
+
 def _preprocess(csource):
     # Remove comments.  NOTE: this only work because the cdef() section
     # should not contain any string literal!
@@ -506,6 +513,7 @@ class Parser(object):
                     if (quals & model.Q_CONST) and not tp.is_array_type:
                         self._declare('constant ' + decl.name, tp, quals=quals)
                     else:
+                        _warn_for_non_extern_non_static_global_variable(decl)
                         self._declare('variable ' + decl.name, tp, quals=quals)
 
     def parse_type(self, cdecl):