svn commit: r309024 - stable/10/sys/sys

[Alan Somers]

Author: asomers
Date: Tue Nov 22 21:02:35 2016
New Revision: 309024
URL: https://svnweb.freebsd.org/changeset/base/309024

Log:
  MFC r307584 (partially)
  
  307584 added the __min_size macro and replaced some static array sizes with
  __min_size.  However, stable/10 doesn't yet have any static array sizes, so
  all this MFC does is add the __min_size macro.
  
  Original commit message:
  
  Fix C++ includability of crypto headers with static array sizes
  
  C99 allows array function parameters to use the static keyword for their
  sizes. This tells the compiler that the parameter will have at least the
  specified size, and calling code will fail to compile if that guarantee is
  not met. However, this syntax is not legal in C++.
  
  This commit reverts r300824, which worked around the problem for
  sys/sys/md5.h only, and introduces a new macro: min_size(). min_size(x) can
  be used in headers as a static array size, but will still compile in C++
  mode.

Modified:
  stable/10/sys/sys/cdefs.h
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/sys/cdefs.h
==============================================================================
--- stable/10/sys/sys/cdefs.h	Tue Nov 22 20:28:17 2016	(r309023)
+++ stable/10/sys/sys/cdefs.h	Tue Nov 22 21:02:35 2016	(r309024)
@@ -332,6 +332,20 @@
 	    __builtin_types_compatible_p(__typeof(expr), t), yes, no)
 #endif
 
+/*
+ * C99 Static array indices in function parameter declarations.  Syntax such as:
+ * void bar(int myArray[static 10]);
+ * is allowed in C99 but not in C++.  Define __min_size appropriately so
+ * headers using it can be compiled in either language.  Use like this:
+ * void bar(int myArray[__min_size(10)]);
+ */
+#if !defined(__cplusplus) && \
+    (!defined(__STDC_VERSION) || (__STDC_VERSION__ >= 199901))
+#define __min_size(x)	static (x)
+#else
+#define __min_size(x)	(x)
+#endif
+
 #if __GNUC_PREREQ__(2, 96)
 #define	__malloc_like	__attribute__((__malloc__))
 #define	__pure		__attribute__((__pure__))