I'm trying to build my program using gcc 5 with c++11 enabled.
My makefile calls gccmakedep which then complains about missing c++11 support:
error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options. #error This file requires compiler and library support \
I modified the line in the makefile to set the required option:
gccmakedep -- -std=gnu++11 -- $(SRCS)
It doesn't work. I get the same error. I think gccmakedep doesn't recognize the option.
How can I solve this?
Related
I am trying to build cmake source, which requires C++11.
The build halts and apparently the complaint is that C++11 is not detected. The g++ mode is actually set to -std=gnu++17
This is part of the console log
---------------------------------------------
CMake 3.18.20200919, Copyright 2000-2020 Kitware, Inc. and Contributors
Found GNU toolchain
C compiler on this system is: gcc
C++ compiler on this system is: g++ -std=gnu++17
Makefile processor on this system is: make
g++ has setenv
g++ has unsetenv
g++ does not have environ in stdlib.h
g++ has stl wstring
g++ has <ext/stdio_filebuf.h>
---------------------------------------------
g++ -std=gnu++17 -DCMAKE_BOOTSTRAP -DCMake_HAVE_CXX_MAKE_UNIQUE=1 -c $HOME/Apps/CMake-master/Source/cmAddCustomCommandCommand.cxx -o cmAddCustomCommandCommand.o
This is part of the error in the log file...
In file included from /usr/include/c++/5/unordered_map:35:0,
from cmake_bootstrap_11920_test.cxx:4:
/usr/include/c++/5/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
#error This file requires compiler and library support \
^
cmake_bootstrap_11920_test.cxx:7:2: error: #error "Compiler is not in a mode aware of C++11."
#error "Compiler is not in a mode aware of C++11."
^
cmake_bootstrap_11920_test.cxx:70:16: warning: non-static data member initializers only available with -std=c++11 or -std=gnu++11
int Member = 1;
Looking around on the web, I noticed that C++11 is only available after gcc version 4.6.
I checked my version, and it seems to be above.
g++ --version
g++ (Ubuntu 5.4.0-6ubuntu1~16.04.12) 5.4.0 20160609
I understand the -std=c++11 flag is used to enable the C++11 features in g++, but I don't seem to know what I am doing in this case.
I tried editing the CompileFlags.cmake file, but no change occurs.
I came upon this page which points to the cmake source I am using.
It says...
bootstrap: Require compiler mode aware of C++11
Some compilers have enough features enabled in their default modes to
pass our simple C++11 unique_ptr check but do not enable enough to build
CMake. Poison this case so that we choose one of the explicit `-std=`
options for such compilers.
Not sure what that means exactly.
How exactly do I change the g++ mode, to C++11, so that on running the bootstrap command, C++11 is used?
Or, in other words, how do I change std to point to C++11 (-std=c++11)?
First of all, you have g++ version 5.4.0 in your host PC installed, which is good, cause it means this is also supports the C++11, which you want to use.
To set it up, you could define it in your CMakeList.txt file:
set (CMAKE_CXX_STANDARD 11)
that should do the trick.
Please also check the documentation:
https://cmake.org/cmake/help/v3.1/variable/CMAKE_CXX_STANDARD.html
Usually, I would suggest to use the latest standard that you compiler is supporting (https://gcc.gnu.org/projects/cxx-status.html), cause you'll get also the latest features introduced in that standard. Exception for this rather in case you are working with legacy codes.
I want to use a timer as advised in
How can I measure the execution time of one thread?
However, I receive the error message
In file included from /usr/include/c++/5/thread:35:0,
/usr/include/c++/5/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
#error This file requires compiler and library support \
^
The CMake output of
message("${CMAKE_CXX_FLAGS}" and "${CMAKE_C_FLAGS}")
is
-std=c++11 -fPIC -Wall;and; -std=c++11
What is wrong?
If you would like your project to require C++11, I suggest you do something like this:
cmake_minimum_required(VERSION 3.10)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
project(test)
[...]
If you are building a library, and you would like user of your library to transitively use the correct flags, you could look into https://cmake.org/cmake/help/latest/manual/cmake-compile-features.7.html#requiring-language-standards
The version of compiler is 4.4.6 and it should support c++0x as indicated here: https://gcc.gnu.org/gcc-4.4/cxx0x_status.html
But I still get below compile error:
*In file included from /usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../include/c++/4.4.6/cinttypes:35,
...
/usr/lib/gcc/x86_64-redhat-linux/4.4.6/../../../../include/c++/4.4.6/c++0x_warning.h:31:2:
error: #error This file requires compiler and library support for the
upcoming ISO C++ standard, C++0x. This support is currently
experimental, and must be enabled with the -std=c++0x or -std=gnu++0x
compiler options.*
The flag is already added in makefile as below:
g++ **-std=c++0x** $(LDFLAGS) $(Objs) -o Test
I tried -std=gnu++0x but doesn't work.
You have added the option to your link command, not your compile command. You need to add it to CXXFLAGS.
I am compiling one code repository which has a makefile,
make INSTALL_PREFIX=/usr/local install
and I get the following error:
This file requires compiler and library support for the ISO C++ 2011
standard. This support must be enabled with the -std=c++11 or
-std=gnu++11 compiler options.
How can I enable ISO C++ 2011 standard?
Thanks,
You don't give any details on the code repository, does it use just a standard makefile, autotools, cmake ?
You may be able to just do a export CPPFLAGS="-std=c++11" prior to building building the code.
I've recently downloaded CUDA 7 and set it up to work with my project. On Mac, CUDA 7 requires clang to be the host compiler.
Now, I'm using a number of C++11 features. I've enabled these with -std=c++11 passed to nvcc this works. However, if I pass -Xcompiler -std=c++11 to nvcc, I get the following error regardless of if I also passed -std=c++11 by itself. The error is:
"invalid argument '-std=c++11' not allowed with 'C/ObjC'"
It seems like this should work, it certainly does with GCC. Anyone have a workaround. Otherwise, I'll file a bug report with Nvidia.
nvcc -dryrun ... will show what commands nvcc will execute. I don't currently have access to CUDA 7, only 6.5, but mine issues, among other things, two commands that compiles generated C source. This code generated by cudafe and have to be compiled by C compiler, but -Xcompiler adds options for both C and C++ modes.
I guess difference with my gcc situation is that I'm getting a warning while you have an error (this is exactly how gcc and clang differs in that case). For both compilers I don't see any way to suppress it, so I guess you have to fix your .cmake files to omit -Xcompiler options. This options shouldn't be used for language standard, just some very compiler-specific things.
Of course it doesn't work. You are specifying C++ options while using a C or Objective-C compiler. The source files must be C++ or Objective-C++.