Add cmake module finding the appropriate variant of the "restrict" keyword.

Could that be useful to have in kdelibs/cmake/modules ?

1 files changed, 87 insertions, 0 deletions

diff --git a/cmake/CheckRestrictKeyword.cmake b/cmake/CheckRestrictKeyword.cmake
new file mode 100644
index 000000000..d3fcbda90
--- /dev/null
+++ b/cmake/CheckRestrictKeyword.cmake
@@ -0,0 +1,87 @@
+# This module checks if the C++ compiler supports the restrict keyword or
+# some variant of it. The following variants are checked for in that order:
+# 1. restrict            (The standard C99 keyword, not yet in C++ standard)
+# 2. __restrict          (G++ has it)
+# 3. __restrict__        (G++ has it too)
+# 4. _Restrict           (seems to be used by Sun's compiler)
+# These four cases seem to cover all existing variants; however some C++
+# compilers don't support any variant, in which case the _RESULT variable is
+# set to empty value.
+#
+# Copyright Benoit Jacob 2007 <jacob@math.jussieu.fr>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file in
+# kdelibs/cmake/modules.
+
+INCLUDE(CheckCXXSourceCompiles)
+
+MACRO (CHECK_RESTRICT_KEYWORD _RESULT)
+
+SET(_CHECK_restrict_KEYWORD_SRC "
+
+char f( const char * restrict x )
+{
+  return *x;
+}
+
+int main(int argc, char *argv[]) { return 0; } 
+")
+
+SET(_CHECK___restrict_KEYWORD_SRC "
+
+char f( const char * __restrict x )
+{
+  return *x;
+}
+
+int main(int argc, char *argv[]) { return 0; } 
+")
+
+SET(_CHECK___restrict___KEYWORD_SRC "
+
+char f( const char * __restrict__ x )
+{
+  return *x;
+}
+
+int main(int argc, char *argv[]) { return 0; } 
+")
+
+SET(_CHECK__Restrict_KEYWORD_SRC "
+
+char f( const char * _Restrict x )
+{
+  return *x;
+}
+
+int main(int argc, char *argv[]) { return 0; } 
+")
+
+CHECK_CXX_SOURCE_COMPILES("${_CHECK_restrict_KEYWORD_SRC}"
+                          HAVE_KEYWORD_restrict)
+IF(HAVE_KEYWORD_restrict)
+  SET(${_RESULT} restrict)
+ELSE(HAVE_KEYWORD_restrict)
+  CHECK_CXX_SOURCE_COMPILES("${_CHECK___restrict_KEYWORD_SRC}"
+                          HAVE_KEYWORD___restrict)
+  IF(HAVE_KEYWORD___restrict)
+    SET(${_RESULT} __restrict)
+  ELSE(HAVE_KEYWORD___restrict)
+    CHECK_CXX_SOURCE_COMPILES("${_CHECK___restrict___KEYWORD_SRC}"
+                            HAVE_KEYWORD___restrict__)
+    IF(HAVE_KEYWORD___restrict__)
+      SET(${_RESULT} __restrict__)
+    ELSE(HAVE_KEYWORD___restrict__)
+      CHECK_CXX_SOURCE_COMPILES("${_CHECK__Restrict_KEYWORD_SRC}"
+                            HAVE_KEYWORD__Restrict)
+      IF(HAVE_KEYWORD__Restrict)
+        SET(${_RESULT} _Restrict)
+      ELSE(HAVE_KEYWORD__Restrict)
+        SET(${_RESULT} ) # no variant of restrict keyword supported
+      ENDIF(HAVE_KEYWORD__Restrict)
+    ENDIF(HAVE_KEYWORD___restrict__)
+  ENDIF(HAVE_KEYWORD___restrict)
+ENDIF(HAVE_KEYWORD_restrict)
+
+ENDMACRO (CHECK_RESTRICT_KEYWORD)