container_of: work with -Wcast-qual

[ccan] / ccan / container_of / container_of.h

diff --git a/ccan/container_of/container_of.h b/ccan/container_of/container_of.h
index 1c9d147ae06df9f4e0e54adea977f6087e4c628d..0449935056f51a84af2a84f5b2dd7fcbf48c7678 100644 (file)
--- a/ccan/container_of/container_of.h
+++ b/ccan/container_of/container_of.h
@@ -1,3 +1,4 @@
+/* CC0 (Public domain) - see LICENSE file for details */
 #ifndef CCAN_CONTAINER_OF_H
 #define CCAN_CONTAINER_OF_H
 #include <stddef.h>
@@ -102,7 +103,7 @@
        container_off(typeof(*var), member)
 #else
 #define container_off_var(var, member)                 \
-       ((char *)&(var)->member - (char *)(var))
+       ((const char *)&(var)->member - (const char *)(var))
 #endif
 
 #endif /* CCAN_CONTAINER_OF_H */