Ubuntu 18.04，gcc版本6.4.0 20180424（Ubuntu 6.4.0-17ubuntu1）
以下调用Openfoam2.3.1（计算流体动力学（CFD）类库）中的Eigen库的程序构建环境，它是由g ++-5编译器构建的。
OpenFOAM 2.3.1 shell环境：源\ $ HOME / OpenFOAM / OpenFOAM-2.3.1 / etc / bashrc $ FOAM_SETTINGS；出口WM_CC = gcc-5;导出WM_CXX = g ++-5
#include <iostream>
#include <Eigen/Dense>
using namespace std;
int main()
{
cout << "hello CFD" << endl;
return 0;
}
我有这种感觉
./Eigen/src/Core/util/XprHelper.h:438:68: warning: use of old-style cast [-Wold-style-cast]
enum { diag_size = EIGEN_SIZE_MIN_PREFER_DYNAMIC(ExpressionType::RowsAtCompileTime, ExpressionType::ColsAtCompileTime),
^
./Eigen/src/Core/util/Macros.h:376:51: note: in definition of macro ‘EIGEN_SIZE_MIN_PREFER_DYNAMIC’
#define EIGEN_SIZE_MIN_PREFER_DYNAMIC(a,b) (((int)a == 0 || (int)b == 0) ? 0 \
^
./Eigen/src/Core/util/XprHelper.h:438:103: warning: use of old-style cast [-Wold-style-cast]
enum { diag_size = EIGEN_SIZE_MIN_PREFER_DYNAMIC(ExpressionType::RowsAtCompileTime, ExpressionType::ColsAtCompileTime),
^
./Eigen/src/Core/util/Macros.h:376:66: note: in definition of macro ‘EIGEN_SIZE_MIN_PREFER_DYNAMIC’
#define EIGEN_SIZE_MIN_PREFER_DYNAMIC(a,b) (((int)a == 0 || (int)b == 0) ? 0 \
^
./Eigen/src/Core/util/XprHelper.h:438:68: warning: use of old-style cast [-Wold-style-cast]
enum { diag_size = EIGEN_SIZE_MIN_PREFER_DYNAMIC(ExpressionType::RowsAtCompileTime, ExpressionType::ColsAtCompileTime),
^
当我使用g ++编译该程序时，不会收到此警告。
你能帮我吗？