Merge topic 'CheckTypeSize-doc-10579'

c6fed68 CheckTypeSize: add a test for size of struct members
48783b7 CheckTypeSize: show in documentation how to get struct member size (#10579)

Modules/CheckTypeSize.cmake

@@ -24,6 +24,11 @@
 # size check automatically includes the available headers, thus
 # supporting checks of types defined in the headers.
 #
+# Despite the name of the macro you may use it to check the size of
+# more complex expressions, too. To check e.g. for the size of a struct
+# member you can do something like this:
+#  check_type_size("((struct something*)0)->member" SIZEOF_MEMBER)
+#
 # The following variables may be set before calling this macro to
 # modify the way the check is run:
 #

Tests/Module/CheckTypeSize/CMakeLists.txt

@@ -12,7 +12,13 @@ check_type_size(__int64     SIZEOF___INT64)
 check_type_size(size_t      SIZEOF_SIZE_T)
 check_type_size(ssize_t     SIZEOF_SSIZE_T)
 
+set(CMAKE_REQUIRED_INCLUDES "${CMAKE_CURRENT_SOURCE_DIR}")
+set(CMAKE_EXTRA_INCLUDE_FILES somestruct.h)
+check_type_size("((struct somestruct*)0)->someint" SIZEOF_STRUCTMEMBER_INT)
+check_type_size("((struct somestruct*)0)->someptr" SIZEOF_STRUCTMEMBER_PTR)
+check_type_size("((struct somestruct*)0)->somechar" SIZEOF_STRUCTMEMBER_CHAR)
+
 configure_file(config.h.in config.h)
-include_directories(${CheckTypeSize_BINARY_DIR})
+include_directories("${CheckTypeSize_BINARY_DIR}")
 
 add_executable(CheckTypeSize CheckTypeSize.c)

Tests/Module/CheckTypeSize/CheckTypeSize.c

@@ -1,4 +1,5 @@
 #include "config.h"
+#include "somestruct.h"
 
 #ifdef HAVE_SYS_TYPES_H
 # include <sys/types.h>
@@ -29,6 +30,7 @@
 int main()
 {
   int result = 0;
+  struct somestruct x;
 
   /* void* */
 #if !defined(HAVE_SIZEOF_DATA_PTR)
@@ -118,5 +120,41 @@ int main()
   NODEF(SIZEOF_SSIZE_T);
 #endif
 
-  return result;
+  /* struct somestruct::someint */
+#if defined(SIZEOF_STRUCTMEMBER_INT)
+  CHECK(x.someint, SIZEOF_STRUCTMEMBER_INT);
+  CHECK(x.someint, SIZEOF_INT);
+# if !defined(HAVE_SIZEOF_STRUCTMEMBER_INT)
+  NODEF(HAVE_SIZEOF_STRUCTMEMBER_INT);
+# endif
+#elif defined(HAVE_SIZEOF_STRUCTMEMBER_INT)
+  NODEF(SIZEOF_STRUCTMEMBER_INT);
+#endif
+
+  /* struct somestruct::someptr */
+#if defined(SIZEOF_STRUCTMEMBER_PTR)
+  CHECK(x.someptr, SIZEOF_STRUCTMEMBER_PTR);
+  CHECK(x.someptr, SIZEOF_DATA_PTR);
+# if !defined(HAVE_SIZEOF_STRUCTMEMBER_PTR)
+  NODEF(HAVE_SIZEOF_STRUCTMEMBER_PTR);
+# endif
+#elif defined(HAVE_SIZEOF_STRUCTMEMBER_PTR)
+  NODEF(SIZEOF_STRUCTMEMBER_PTR);
+#endif
+
+  /* struct somestruct::someint */
+#if defined(SIZEOF_STRUCTMEMBER_CHAR)
+  CHECK(x.somechar, SIZEOF_STRUCTMEMBER_CHAR);
+  CHECK(x.somechar, SIZEOF_CHAR);
+# if !defined(HAVE_SIZEOF_STRUCTMEMBER_CHAR)
+  NODEF(HAVE_SIZEOF_STRUCTMEMBER_CHAR);
+# endif
+#elif defined(HAVE_SIZEOF_STRUCTMEMBER_CHAR)
+  NODEF(SIZEOF_STRUCTMEMBER_CHAR);
+#endif
+
+  /* to avoid possible warnings about unused or write-only variable */
+  x.someint = result;
+
+  return x.someint;
 }

Tests/Module/CheckTypeSize/config.h.in

@@ -37,3 +37,15 @@
 /* ssize_t */
 #cmakedefine HAVE_SIZEOF_SSIZE_T
 @SIZEOF_SSIZE_T_CODE@
+
+/* struct somestruct::someint */
+#cmakedefine HAVE_SIZEOF_STRUCTMEMBER_INT
+@SIZEOF_STRUCTMEMBER_INT_CODE@
+
+/* struct somestruct::someptr */
+#cmakedefine HAVE_SIZEOF_STRUCTMEMBER_PTR
+@SIZEOF_STRUCTMEMBER_PTR_CODE@
+
+/* struct somestruct::somechar */
+#cmakedefine HAVE_SIZEOF_STRUCTMEMBER_CHAR
+@SIZEOF_STRUCTMEMBER_CHAR_CODE@

Tests/Module/CheckTypeSize/somestruct.h

@@ -0,0 +1,10 @@
+#ifndef _CMAKE_SOMESTRUCT_H
+#define _CMAKE_SOMESTRUCT_H
+
+struct somestruct {
+    int someint;
+    void *someptr;
+    char somechar;
+};
+
+#endif