utils/macros.h: Introduce a `STATIC_ASSERT' macro.

diff --git a/utils/macros.3 b/utils/macros.3
index a2a90033b5e87ac95cffeeb8ecdd6bf35a5b11c2..98ab23861629d91f2e4025e194bf29a942d46839 100644 (file)
--- a/utils/macros.3
+++ b/utils/macros.3
@@ -5,6 +5,7 @@ macros \- useful macros
 .\" @N
 .\" @STR
 .\" @GLUE
 .\" @N
 .\" @STR
 .\" @GLUE

+.\" @STATIC_ASSERT

 .\" @DISCARD
 .\" @IGNORE
 .\" @DEPRECATED
 .\" @DISCARD
 .\" @IGNORE
 .\" @DEPRECATED


@@ -24,6 +25,7 @@ macros \- useful macros
 .BI "size_t N(" array ");"
 .BI "STR(" tokens\fR... ")"
 .BI "GLUE(" tokens\fR... ", " tokens\fR... ")"
 .BI "size_t N(" array ");"
 .BI "STR(" tokens\fR... ")"
 .BI "GLUE(" tokens\fR... ", " tokens\fR... ")"

+.BI "STATIC_ASSERT(" cond ", " msg ");"

 
 .BI "void DISCARD(" scalar ");"
 .BI "void IGNORE(" variable ");"
 
 .BI "void DISCARD(" scalar ");"
 .BI "void IGNORE(" variable ");"


@@ -64,6 +66,18 @@ and the result of gluing these tokens together must be valid
 preprocessing token.
 .PP
 The
 preprocessing token.
 .PP
 The

+.B STATIC_ASSERT
+causes compilation to fail if the integer constant expression
+.I cond
+evaluates to zero.  This macro uses the C11
+.B static_assert
+declaration if available, and the
+.I msg
+will be reported in the compiler's diagnostic messsage; otherwise, the macro
+falls back to a somewhat ugly hack which currently ignores the
+.IR msg .
+.PP
+The

 .B DISCARD
 macro discards its argument, which must be of some scalar type.  This
 can be useful in muffling warnings about ignoring return codes in cases
 .B DISCARD
 macro discards its argument, which must be of some scalar type.  This
 can be useful in muffling warnings about ignoring return codes in cases

diff --git a/utils/macros.h b/utils/macros.h
index 5f432f7e9b3c25b82884214df5bb3d388702add9..9e27a4813a4b3f8997e2ba85784d587023d87778 100644 (file)
--- a/utils/macros.h
+++ b/utils/macros.h
@@ -34,6 +34,8 @@
 
 /*----- Header files ------------------------------------------------------*/
 
 
 /*----- Header files ------------------------------------------------------*/
 

+#include <assert.h>
+

 #ifndef MLIB_COMPILER_H
 #  include "compiler.h"
 #endif
 #ifndef MLIB_COMPILER_H
 #  include "compiler.h"
 #endif


@@ -48,6 +50,13 @@
 #define MLIB__GLUE(x, y) x##y
 #define GLUE(x, y) MLIB__GLUE(x, y)
 
 #define MLIB__GLUE(x, y) x##y
 #define GLUE(x, y) MLIB__GLUE(x, y)
 

+#ifdef static_assert
+#  define STATIC_ASSERT(cond, msg) static_assert(cond, msg)
+#else
+#  define STATIC_ASSERT(cond, msg)                                     \
+       IGNORABLE extern char static_assert_failed[2*!!(cond) - 1]
+#endif
+

 /*----- Compiler diagnostics ----------------------------------------------*/
 
 /* --- Compiler-specific definitions --- */
 /*----- Compiler diagnostics ----------------------------------------------*/
 
 /* --- Compiler-specific definitions --- */