removed some documentation referencing c++98 behaviour

Eigen/src/Core/DiagonalMatrix.h

@@ -180,9 +180,7 @@ class DiagonalMatrix
     EIGEN_DEVICE_FUNC
     inline DiagonalMatrix(const Scalar& x, const Scalar& y, const Scalar& z) : m_diagonal(x,y,z) {}
 
-    /** \brief Construct a diagonal matrix with fixed size from an arbitrary number of coefficients. \cpp11
+    /** \brief Construct a diagonal matrix with fixed size from an arbitrary number of coefficients.
-      * 
-      * There exists C++98 anologue constructors for fixed-size diagonal matrices having 2 or 3 coefficients.
       * 
       * \warning To construct a diagonal matrix of fixed size, the number of values passed to this 
       * constructor must match the fixed dimension of \c *this.

Eigen/src/Core/PlainObjectBase.h

@@ -548,12 +548,11 @@ class PlainObjectBase : public internal::dense_xpr_base<Derived>::type
 //       EIGEN_INITIALIZE_COEFFS_IF_THAT_OPTION_IS_ENABLED
     }
 
-    /** \brief Construct a row of column vector with fixed size from an arbitrary number of coefficients. \cpp11
+    /** \brief Construct a row of column vector with fixed size from an arbitrary number of coefficients.
       *
       * \only_for_vectors
       *
       * This constructor is for 1D array or vectors with more than 4 coefficients.
-      * There exists C++98 analogue constructors for fixed-size array/vector having 1, 2, 3, or 4 coefficients.
       *
       * \warning To construct a column (resp. row) vector of fixed length, the number of values passed to this
       * constructor must match the the fixed number of rows (resp. columns) of \c *this.
@@ -574,7 +573,7 @@ class PlainObjectBase : public internal::dense_xpr_base<Derived>::type
     }
 
     /** \brief Constructs a Matrix or Array and initializes it by elements given by an initializer list of initializer
-      * lists \cpp11
+      * lists
       */
     EIGEN_DEVICE_FUNC
     explicit EIGEN_STRONG_INLINE PlainObjectBase(const std::initializer_list<std::initializer_list<Scalar>>& list)

Eigen/src/Core/Reshaped.h

@@ -29,10 +29,9 @@ namespace Eigen {
   * It is the return type of DenseBase::reshaped(NRowsType,NColsType) and
   * most of the time this is the only way it is used.
   *
-  * However, in C++98, if you want to directly maniputate reshaped expressions,
+  * If you want to directly manipulate reshaped expressions,
-  * for instance if you want to write a function returning such an expression, you
+  * for instance if you want to write a function returning such an expression,
-  * will need to use this class. In C++11, it is advised to use the \em auto
+  * it is advised to use the \em auto keyword for such use cases.
-  * keyword for such use cases.
   *
   * Here is an example illustrating the dynamic case:
   * \include class_Reshaped.cpp

Eigen/src/Core/util/IntegralConstant.h

@@ -31,10 +31,8 @@ template<int N> class VariableAndFixedInt;
   *  - arithmetic and some bitwise operators: -, +, *, /, %, &, |
   *  - c++98/14 compatibility with fix<N> and fix<N>() syntax to define integral constants.
   *
-  * It is strongly discouraged to directly deal with this class FixedInt. Instances are expcected to
+  * It is strongly discouraged to directly deal with this class FixedInt. Instances are expected to
-  * be created by the user using Eigen::fix<N> or Eigen::fix<N>(). In C++98-11, the former syntax does
+  * be created by the user using Eigen::fix<N> or Eigen::fix<N>().
-  * not create a FixedInt<N> instance but rather a point to function that needs to be \em cleaned-up
-  * using the generic helper:
   * \code
   * internal::cleanup_index_type<T>::type
   * internal::cleanup_index_type<T,DynamicKey>::type
@@ -191,14 +189,6 @@ static const internal::FixedInt<N> fix{};
   * <a href="http://en.cppreference.com/w/cpp/types/integral_constant">\c std::integral_constant </a><tt> <int,N> </tt>
   * Here, \c fix<N> is thus an object of type \c internal::FixedInt<N>.
   *
-  * In c++98/11, it is implemented as a function:
-  * \code
-  * template<int N> inline internal::FixedInt<N> fix();
-  * \endcode
-  * Here internal::FixedInt<N> is thus a pointer to function.
-  *
-  * If for some reason you want a true object in c++98 then you can write: \code fix<N>() \endcode which is also valid in c++14.
-  *
   * \sa fix<N>(int), seq, seqN
   */
 template<int N>

Eigen/src/Core/util/SymbolicIndex.h

@@ -32,9 +32,6 @@ namespace Eigen {
   * // And evaluate it: (c++14)
   * std::cout << expr.eval(x=6,y=3,z=-13) << "\n";
   *
-  * // In c++98/11, only one symbol per expression is supported for now:
-  * auto expr98 = (3-x)/2;
-  * std::cout << expr98.eval(x=6) << "\n";
   * \endcode
   *
   * It is currently only used internally to define and manipulate the

doc/StructHavingEigenMembers.dox

@@ -80,7 +80,7 @@ But AVX instructions (at least the ones that %Eigen uses, which are the fast one
 Otherwise you get a segmentation fault.
 
 For this reason, %Eigen takes care by itself to require 256-bit alignment for Eigen::Vector4d, by doing two things:
-\li %Eigen requires 256-bit alignment for the Eigen::Vector4d's array (of 4 doubles). With \cpp11 this is done with the <a href="https://en.cppreference.com/w/cpp/keyword/alignas">alignas</a> keyword, or compiler's extensions for c++98/03.
+\li %Eigen requires 256-bit alignment for the Eigen::Vector4d's array (of 4 doubles). This is done with the <a href="https://en.cppreference.com/w/cpp/keyword/alignas">alignas</a> keyword.
 \li %Eigen overloads the `operator new` of Eigen::Vector4d so it will always return 256-bit aligned pointers. (removed in \cpp17)
 
 Thus, normally, you don't have to worry about anything, %Eigen handles alignment of operator new for you...