diff --git a/include/cybozu/atoi.hpp b/include/cybozu/atoi.hpp
index a22853a..3930571 100644
--- a/include/cybozu/atoi.hpp
+++ b/include/cybozu/atoi.hpp
@@ -7,7 +7,6 @@
 */
 
 #include <memory.h>
-#include <limits.h>
 #include <limits>
 #include <cybozu/exception.hpp>
 
@@ -173,7 +172,7 @@ public:
 	}
 	inline operator int() const
 	{
-		return atoi_local::convertToInt<int>(b_, p_, size_, "2147483648", INT_MIN, 214748364, '8');
+		return atoi_local::convertToInt<int>(b_, p_, size_, "2147483648", /*INT_MIN*/-2147483648, 214748364, '8');
 	}
 	inline operator unsigned int() const
 	{
@@ -181,7 +180,7 @@ public:
 	}
 	inline operator long long() const
 	{
-		return atoi_local::convertToInt<long long>(b_, p_, size_, "9223372036854775808", LLONG_MIN, 922337203685477580LL, '8');
+		return atoi_local::convertToInt<long long>(b_, p_, size_, "9223372036854775808", CYBOZU_LLONG_MIN, 922337203685477580LL, '8');
 	}
 	inline operator unsigned long long() const
 	{
diff --git a/include/cybozu/exception.hpp b/include/cybozu/exception.hpp
index f5b044f..a9668ba 100644
--- a/include/cybozu/exception.hpp
+++ b/include/cybozu/exception.hpp
@@ -203,7 +203,6 @@ public:
 	}
 	/**
 		convert NativeErrNo to string(maybe UTF8)
-		@param err [in] errno
 		@note Linux   : same as ConvertErrorNoToString
 			  Windows : for Win32 API(use en-us)
 	*/
diff --git a/include/cybozu/inttype.hpp b/include/cybozu/inttype.hpp
index 62856bd..f74a1d1 100644
--- a/include/cybozu/inttype.hpp
+++ b/include/cybozu/inttype.hpp
@@ -72,6 +72,9 @@
 	#endif
 #endif
 
+// LLONG_MIN in limits.h is not defined in some env.
+#define CYBOZU_LLONG_MIN (-9223372036854775807ll-1)
+
 #define CYBOZU_CPP_VERSION_CPP03 0
 #define CYBOZU_CPP_VERSION_TR1 1
 #define CYBOZU_CPP_VERSION_CPP11 2
@@ -88,7 +91,7 @@
 	#define CYBOZU_CPP_VERSION CYBOZU_CPP_VERSION_CPP17
 #elif (__cplusplus >= 201402)
 	#define CYBOZU_CPP_VERSION CYBOZU_CPP_VERSION_CPP14
-#elif (__cplusplus >= 201103) || (_MSC_VER >= 1500) || defined(__GXX_EXPERIMENTAL_CXX0X__)
+#elif (__cplusplus >= 201103) || (defined(_MSC_VER) && _MSC_VER >= 1500) || defined(__GXX_EXPERIMENTAL_CXX0X__)
 	#if defined(_MSC_VER) && (_MSC_VER <= 1600)
 		#define CYBOZU_CPP_VERSION CYBOZU_CPP_VERSION_TR1
 	#else
@@ -150,8 +153,10 @@
 
 #if CYBOZU_CPP_VERSION >= CYBOZU_CPP_VERSION_CPP11
 	#define CYBOZU_NOEXCEPT noexcept
+	#define CYBOZU_NULLPTR nullptr
 #else
 	#define CYBOZU_NOEXCEPT throw()
+	#define CYBOZU_NULLPTR 0
 #endif
 namespace cybozu {
 template<class T>
diff --git a/include/cybozu/itoa.hpp b/include/cybozu/itoa.hpp
index 072e5b8..9686938 100644
--- a/include/cybozu/itoa.hpp
+++ b/include/cybozu/itoa.hpp
@@ -5,7 +5,6 @@
 
 	@author MITSUNARI Shigeo(@herumi)
 */
-#include <limits.h>
 #ifndef CYBOZU_DONT_USE_STRING
 #include <string>
 #endif
@@ -122,7 +121,7 @@ size_t uintToBin(char *buf, size_t bufSize, UT x)
 template<class T>
 size_t intToDec(char *buf, size_t bufSize, T x)
 {
-	if (x == LLONG_MIN) {
+	if (x == CYBOZU_LLONG_MIN) {
 		const char minStr[] = "-9223372036854775808";
 		const size_t minStrLen = sizeof(minStr) - 1;
 		if (bufSize < minStrLen) {