Prototype patch to support <math.h> as a conforming C++ header in addition to <cmath>.

[chandlerc]

Summary

This extracts the conformance fixing aspects of <cmath> (replacing macros with
inline functions) into a <math.h> which wraps the system <math.h>.

This should have no functionality change for <cmath> but will cause
includes of <math.h> to be modular and place nicely in C++ code using
libc++.

Clearly this isn't ready to commit -- it doesn't have a synopsis and I would
rather fix all of the related <cfoo> headers in a single patch, but it should
at least clarify the nature of the approach.

[rsmith]

This looks like a good approach to me.

[mclow.lists]

I am OK with this approach as well.

include/cmath

 }  // std
 
 */
 
 #include <__config>
 #include <math.h>
 #include <type_traits>
 
-#ifdef _LIBCPP_MSVCRT
-#include "support/win32/math_win32.h"
-#endif
-
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #pragma GCC system_header
 #endif
 
-// signbit
-
-#ifdef signbit
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_signbit(_A1 __lcpp_x) _NOEXCEPT
-{
-    return signbit(__lcpp_x);
-}
-
-#undef signbit
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
-signbit(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_signbit((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // signbit
-
-// fpclassify
-
-#ifdef fpclassify
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-int
-__libcpp_fpclassify(_A1 __lcpp_x) _NOEXCEPT
-{
-    return fpclassify(__lcpp_x);
-}
-
-#undef fpclassify
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, int>::type
-fpclassify(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_fpclassify((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // fpclassify
-
-// isfinite
-
-#ifdef isfinite
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isfinite(_A1 __lcpp_x) _NOEXCEPT
-{
-    return isfinite(__lcpp_x);
-}
-
-#undef isfinite
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
-isfinite(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isfinite((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // isfinite
-
-// isinf
-
-#ifdef isinf
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isinf(_A1 __lcpp_x) _NOEXCEPT
-{
-    return isinf(__lcpp_x);
-}
-
-#undef isinf
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
-isinf(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isinf((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // isinf
-
-// isnan
-
-#ifdef isnan
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT
-{
-    return isnan(__lcpp_x);
-}
-
-#undef isnan
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
-isnan(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isnan((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // isnan
-
-// isnormal
-
-#ifdef isnormal
-
-template <class _A1>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isnormal(_A1 __lcpp_x) _NOEXCEPT
-{
-    return isnormal(__lcpp_x);
-}
-
-#undef isnormal
-
-template <class _A1>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
-isnormal(_A1 __lcpp_x) _NOEXCEPT
-{
-    return __libcpp_isnormal((typename std::__promote<_A1>::type)__lcpp_x);
-}
-
-#endif  // isnormal
-
-// isgreater
-
-#ifdef isgreater
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isgreater(__lcpp_x, __lcpp_y);
-}
-
-#undef isgreater
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isgreater((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // isgreater
-
-// isgreaterequal
-
-#ifdef isgreaterequal
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isgreaterequal(__lcpp_x, __lcpp_y);
-}
-
-#undef isgreaterequal
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isgreaterequal((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // isgreaterequal
-
-// isless
-
-#ifdef isless
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isless(__lcpp_x, __lcpp_y);
-}
-
-#undef isless
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isless((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // isless
-
-// islessequal
-
-#ifdef islessequal
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return islessequal(__lcpp_x, __lcpp_y);
-}
-
-#undef islessequal
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_islessequal((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // islessequal
-
-// islessgreater
-
-#ifdef islessgreater
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return islessgreater(__lcpp_x, __lcpp_y);
-}
-
-#undef islessgreater
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_islessgreater((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // islessgreater
-
-// isunordered
-
-#ifdef isunordered
-
-template <class _A1, class _A2>
-_LIBCPP_ALWAYS_INLINE
-bool
-__libcpp_isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    return isunordered(__lcpp_x, __lcpp_y);
-}
-
-#undef isunordered
-
-template <class _A1, class _A2>
-inline _LIBCPP_INLINE_VISIBILITY
-typename std::enable_if
-<
-    std::is_arithmetic<_A1>::value &&
-    std::is_arithmetic<_A2>::value,
-    bool
->::type
-isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
-{
-    typedef typename std::__promote<_A1, _A2>::type type;
-    return __libcpp_isunordered((type)__lcpp_x, (type)__lcpp_y);
-}
-
-#endif  // isunordered
-
 _LIBCPP_BEGIN_NAMESPACE_STD
 
 using ::signbit;
 using ::fpclassify;
 using ::isfinite;
 using ::isinf;
 using ::isnan;
 using ::isnormal;

include/math.h

+// -*- C++ -*-
+//===---------------------------- math.h ----------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_MATH_H
+#define _LIBCPP_MATH_H
+
+#include <__config>
+#include_next <math.h>
+#include <type_traits>
+
+#ifdef _LIBCPP_MSVCRT
+#include "support/win32/math_win32.h"
+#endif
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+// signbit
+
+#ifdef signbit
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_signbit(_A1 __lcpp_x) _NOEXCEPT
+{
+    return signbit(__lcpp_x);
+}
+
+#undef signbit
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+signbit(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_signbit((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // signbit
+
+// fpclassify
+
+#ifdef fpclassify
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+int
+__libcpp_fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{
+    return fpclassify(__lcpp_x);
+}
+
+#undef fpclassify
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, int>::type
+fpclassify(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_fpclassify((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // fpclassify
+
+// isfinite
+
+#ifdef isfinite
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isfinite(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isfinite(__lcpp_x);
+}
+
+#undef isfinite
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+isfinite(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isfinite((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // isfinite
+
+// isinf
+
+#ifdef isinf
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isinf(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isinf(__lcpp_x);
+}
+
+#undef isinf
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+isinf(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isinf((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // isinf
+
+// isnan
+
+#ifdef isnan
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isnan(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isnan(__lcpp_x);
+}
+
+#undef isnan
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+isnan(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isnan((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // isnan
+
+// isnormal
+
+#ifdef isnormal
+
+template <class _A1>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isnormal(_A1 __lcpp_x) _NOEXCEPT
+{
+    return isnormal(__lcpp_x);
+}
+
+#undef isnormal
+
+template <class _A1>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if<std::is_arithmetic<_A1>::value, bool>::type
+isnormal(_A1 __lcpp_x) _NOEXCEPT
+{
+    return __libcpp_isnormal((typename std::__promote<_A1>::type)__lcpp_x);
+}
+
+#endif  // isnormal
+
+// isgreater
+
+#ifdef isgreater
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isgreater(__lcpp_x, __lcpp_y);
+}
+
+#undef isgreater
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isgreater((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // isgreater
+
+// isgreaterequal
+
+#ifdef isgreaterequal
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isgreaterequal(__lcpp_x, __lcpp_y);
+}
+
+#undef isgreaterequal
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isgreaterequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isgreaterequal((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // isgreaterequal
+
+// isless
+
+#ifdef isless
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isless(__lcpp_x, __lcpp_y);
+}
+
+#undef isless
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isless(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isless((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // isless
+
+// islessequal
+
+#ifdef islessequal
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return islessequal(__lcpp_x, __lcpp_y);
+}
+
+#undef islessequal
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+islessequal(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_islessequal((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // islessequal
+
+// islessgreater
+
+#ifdef islessgreater
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return islessgreater(__lcpp_x, __lcpp_y);
+}
+
+#undef islessgreater
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+islessgreater(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_islessgreater((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // islessgreater
+
+// isunordered
+
+#ifdef isunordered
+
+template <class _A1, class _A2>
+_LIBCPP_ALWAYS_INLINE
+bool
+__libcpp_isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    return isunordered(__lcpp_x, __lcpp_y);
+}
+
+#undef isunordered
+
+template <class _A1, class _A2>
+inline _LIBCPP_INLINE_VISIBILITY
+typename std::enable_if
+<
+    std::is_arithmetic<_A1>::value &&
+    std::is_arithmetic<_A2>::value,
+    bool
+>::type
+isunordered(_A1 __lcpp_x, _A2 __lcpp_y) _NOEXCEPT
+{
+    typedef typename std::__promote<_A1, _A2>::type type;
+    return __libcpp_isunordered((type)__lcpp_x, (type)__lcpp_y);
+}
+
+#endif  // isunordered
+
+#endif  // _LIBCPP_MATH_H