X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flibpspp%2Fcast.h;h=00e42d6603cc68963f498c6d5ce0ab780c1b19f6;hb=49c02dd0d35698fd43528c4422b3b5202b481a11;hp=5c64fac864a8e1eb78588dcc7558177d759ce0e1;hpb=535b3ff175221bf40a3e009930e4121e6d093f24;p=pspp

diff --git a/src/libpspp/cast.h b/src/libpspp/cast.h
index 5c64fac864..00e42d6603 100644
--- a/src/libpspp/cast.h
+++ b/src/libpspp/cast.h
@@ -112,4 +112,11 @@
         (CHECK_POINTER_COMPATIBILITY (&((STRUCT *) 0)->MEMBER, POINTER), \
          (STRUCT *) ((char *) (POINTER) - offsetof (STRUCT, MEMBER)))
 
+/* A null pointer constant suitable for use in a varargs parameter list.
+
+   This is useful because a literal 0 may not have the same width as a null
+   pointer.  NULL by itself is also insufficient because in C it may expand to
+   simply 0. */
+#define NULL_SENTINEL ((void *) NULL)
+
 #endif /* libpspp/cast.h */