Issue #12837: Silence a Clang compiler warning on OS X.
Now makes CPython build without warnings on OS X under Clang with
-Wno-unused-value -Wno-empty-body -Qunused-arguments
-Wno-deprecated-declarations.
Thanks to David Watson for taking an initial stab at a solution.
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 0aba591..6c229bc 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -1885,8 +1885,22 @@
sizeof(cmsgh->cmsg_len));
/* Note that POSIX allows msg_controllen to be of signed type. */
- if (cmsgh == NULL || msg->msg_control == NULL || msg->msg_controllen < 0)
+ if (cmsgh == NULL || msg->msg_control == NULL)
return 0;
+ /* Note that POSIX allows msg_controllen to be of a signed type. This is
+ annoying under OS X as it's unsigned there and so it triggers a
+ tautological comparison warning under Clang when compared against 0.
+ Since the check is valid on other platforms, silence the warning under
+ Clang. */
+ #ifdef __clang__
+ #pragma clang diagnostic push
+ #pragma clang diagnostic ignored "-Wtautological-compare"
+ #endif
+ if (msg->msg_controllen < 0)
+ return 0;
+ #ifdef __clang__
+ #pragma clang diagnostic pop
+ #endif
if (space < cmsg_len_end)
space = cmsg_len_end;
cmsg_offset = (char *)cmsgh - (char *)msg->msg_control;