The C++ compiler does not support C++11 during bootstrap for cmake

What is CMAKE?

CMake is an open-source, cross-platform family of tools designed to build, test and package software. CMake is used to control the software compilation process using simple platform and compiler independent configuration files, and generate native makefiles and workspaces that can be used in the compiler environment of your choice. 

You can download the latest cmake from

Prerequisites that I use

  • gnu-6.5
  • m4-1.4.18
  • gmp-6.1.0
  • mpfr-3.1.4
  • mpc-1.0.3
  • isl-0.18
  • gsl-2.1

Step 1: You can use the bootstrap which will default the cmake to default location ie /usr/local/. If you are using bootstrap,

# tar -zxvf cmake-3.21.3.tar.gz
# cd cmake-3.21.3 
# ./bootstrap 
# make 
# make install

Errors encountered

CMake 3.21.3, Copyright 2000-2021 Kitware, Inc. and Contributors
Found GNU toolchain
C compiler on this system is: gcc
C++ compiler on this system is: g++  -std=gnu++1y
Makefile processor on this system is: gmake
g++ has setenv
g++ has unsetenv
g++ does not have environ in stdlib.h
g++ has stl wstring
g++ has <ext/stdio_filebuf.h>
gmake: Warning: File `Makefile' has modification time 0.15 s in the future
gmake: `cmake' is up to date.
gmake: warning:  Clock skew detected.  Your build may be incomplete.
loading initial cache file /myhome/melvin/Downloads/cmake-3.21.3/Bootstrap.cmk/InitialCacheFlags.cmake
CMake Error at CMakeLists.txt:107 (message):
  The C++ compiler does not support C++11 (e.g.  std::unique_ptr).

-- Configuring incomplete, errors occurred!
See also "/myhome/melvin/Downloads/cmake-3.21.3/CMakeFiles/CMakeOutput.log".
See also "/myhome/melvin/Downloads/cmake-3.21.3/CMakeFiles/CMakeError.log".


Step 1: You may want to export this before compiling

export CXXFLAGS="-O3"

Step 2: You might want to move to an unmounted directory like /root and try compiling again with root access.

Alternatively, instead of using ./boostrap, you can use the traditional configure command

#./configure --prefix=/usr/local/cmake-3.21.3
# make
# make install


  1. The C++ compiler does not support C++11 (e.g. std::unique_ptr). building OpenWRT
  2. c++11 std::unique_ptr error cmake 3.11.3 bootstrap

Displaying Intel-MPI Debug Information

The Detailed Information can be found at Displaying MPI Debug Information

The I_MPI_DEBUG environment variable provides a convenient way to get detailed information about an MPI application at runtime. You can set the variable value from 0 (the default value) to 1000. The higher the value, the more debug information you get.

High values of I_MPI_DEBUG can output a lot of information and significantly reduce performance of your application. A value of I_MPI_DEBUG=5 is generally a good starting point, which provides sufficient information to find common errors.

Displaying MPI Debug Information

To redirect the debug information output from stdout to stderr or a text file, use the I_MPI_DEBUG_OUTPUT environment variable

$ mpirun -genv I_MPI_DEBUG=5 -genv I_MPI_DEBUG_OUTPUT=debug_output.txt -n 32 ./mpi_program

I_MPI_DEBUG Arguments

<level>Indicate the level of debug information provided.
0Output no debugging information. This is the default value.
1Output libfabric* version and provider.
2Output information about the tuning file used.
3Output effective MPI rank, pid and node mapping table.
4Output process pinning information.
5Output environment variables specific to the Intel® MPI Library.
> 5Add extra levels of debug information.
<flags>Comma-separated list of debug flags
pidShow process id for each debug message.
tidShow thread id for each debug message for multithreaded library.
timeShow time for each debug message.
datetimeShow time and date for each debug message.
hostShow host name for each debug message.
levelShow level for each debug message.
scopeShow scope for each debug message.
lineShow source line number for each debug message.
fileShow source file name for each debug message.
nofuncDo not show routine name.
norankDo not show rank.
nousrwarnSuppress warnings for improper use case (for example, incompatible combination of controls).
flockSynchronize debug output from different process or threads.
nobufDo not use buffered I/O for debug output.


  1. Displaying MPI Debug Information
  2. Developer Reference: I_MPI_DEBUG