How to build code that contains constant expression with c++11 - c++

Hello I am testing new c++ library : TagParser from Martchus
https://github.com/Martchus/tagparser
I am getting that error when I compile the following code:
CODE:
#include <tagparser/mediafileinfo.h>
#include <tagparser/diagnostics.h>
using namespace TagParser;
// create a MediaFileInfo for high-level access to overall functionality of the library
MediaFileInfo fileInfo;
// create container for errors, warnings, etc.
Diagnostics diag;
...
ERROR:
In file included from /usr/include/c++/5/cstdint:35:0,
from /usr/local/include/c++utilities/conversion/types.h:4,
from /usr/local/include/tagparser/tagtarget.h:6,
from /usr/local/include/tagparser/settings.h:4,
from /usr/local/include/tagparser/abstractcontainer.h:5,
from /usr/local/include/tagparser/mediafileinfo.h:4,
from TagParserTest.cpp:1:
/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.
When I try to build with the -std=c++11 option I get this error:
In file included from /usr/local/include/tagparser/abstractcontainer.h:5:0,
from /usr/local/include/tagparser/mediafileinfo.h:4,
from TagParserTest.cpp:1:
/usr/local/include/tagparser/settings.h: In function ‘constexpr TagParser::TagCreationFlags& TagParser::operator|=(TagParser::TagCreationFlags&, TagParser::TagCreationFlags)’:
/usr/local/include/tagparser/settings.h:53:1: error: expression ‘(lhs = ((TagParser::TagCreationFlags)(((std::underlying_type<TagParser::TagCreationFlags>::type)lhs) | ((std::underlying_type<TagParser::TagCreationFlags>::type)rhs))))’ is not a constant-expression
}
I really don't know how to solve this. Can anyone help me?

Many thanks to Daniel H.
When I use c++14 instead of c++11 it just works fine.
Thanks.

Related

‘numeric_limits’ is not a member of ‘std’

I am trying to compile an application from source, FlyWithLua, which includes the sol2 library.
I am following the instructions but when I run cmake --build ./build I get the following error:
In file included from /home/jon/src/FlyWithLua/src/FloatingWindows
/FLWIntegration.cpp:10:
/home/jon/src/FlyWithLua/src/third_party/sol2/./upstream/sol.hpp: In lambda function:
/home/jon/src/FlyWithLua/src/third_party/sol2/./upstream/sol.hpp:7194:59:
error: ‘numeric_limits’ is not a member of ‘std’
7194 | std::size_t space = (std::numeric_limits<std::size_t>::max)();
There are several other errors on the same line after this, but I guess they might just go away if I can solve this one.
there are several similar issues with the solution to add the following includes to the .hpp file
#include <stdexcept>
#include <limits>
the sol.hpp file includes the following imports:
#include <stddef.h>
#include <limits.h>
https://sol2.readthedocs.io/en/latest/errors.html gives some hints about the why the compiler might not recognize these includes:
Compiler Errors / Warnings
A myriad of compiler errors can occur when something goes wrong. Here
is some basic advice about working with these types:
If there are a myriad of errors relating to std::index_sequence, type traits,
and other std:: members, it is likely you have not turned on your C++14 switch for
your compiler. Visual Studio 2015 turns these on by default, but g++ and clang++
do not have them as defaults and you should pass the flag --std=c++1y or
--std=c++14, or similar for your compiler.
the src/CMakeList.txt file has the following line:
set(CMAKE_CXX_STANDARD 17)
I'm only faintly familiar with C/C++ and this all seems very complicated to me, but I'm hoping that there might be an easily recognizable cause and solution to this to someone more skilled.
cat /etc/*-release gives
DISTRIB_RELEASE=21.10
DISTRIB_CODENAME=impish
DISTRIB_DESCRIPTION="Ubuntu 21.10"
$ g++ --version
g++ (Ubuntu 11.2.0-7ubuntu2) 11.2.0
/home/jon/src/FlyWithLua/src/third_party/sol2/./upstream/sol.hpp:7194:59:
error: ‘numeric_limits’ is not a member of ‘std’
7194 | std::size_t space = (std::numeric_limits<std::size_t>::max)();
This error message implies that src/third_party/sol2/./upstream/sol.hpp header uses std::numeric_limits, but also that std::numeric_limits hasn't been defined. The simplest explanation for that is that the header that defines std::numeric_limits hasn't been included. In such case, the solution is to include the header that defines std::numeric_limits.
the sol.hpp file includes the following imports:
#include <stddef.h>
#include <limits.h>
This confirms the problem. Neither of those headers define std::numeric_limits.
https://sol2.readthedocs.io/en/latest/errors.html gives some hints about the why the compiler might not recognize these includes:
Those hints may apply to some other cases, but not this one. std::numeric_limits has been part of the C++ standard since the beginning, so language version has no effect on its existence.
Conclusion: According to the quoted error message, sol.hpp uses std::numeric_limits which is defined in the header <limits>, but according to you, it doesn't include that header. If this is the case, then this is a bug in the sol.hpp file. Correct solution would be to fix the sol.hpp file by including <limits> in that file before using std::numeric_limits.

Adding C++ code in C program - expected ‘,’ or ‘...’ before ‘this’

I am building a C program with no problem on CentOS using provided Makefiles in its distro package. However I need to modify source files and I need to use iqxmlrpc and boost libraries for that purpose. I have changed Makefiles respectively but when I want to build the package I get following error:
../src/libiqxmlrpc/libiqxmlrpc/except.h:9:21: error: stdexcept: No such file or directory
../src/libiqxmlrpc/libiqxmlrpc/except.h:10:18: error: string: No such file or directory
In file included from ../src/libiqxmlrpc/libiqxmlrpc/libiqxmlrpc.h:17,
from redir.c:2617:
../src/libiqxmlrpc/libiqxmlrpc/except.h:14: error: expected '=', ',', ';', 'asm' or 'attribute' before 'iqxmlrpc'
... followed by many other errors ...
I believe above error is because iqxmlpc is written in c++ and gcc is treating it as C so I tried followings:
1) Use g++
2) Use gcc -x c++
Doing above, error changes to a lot of following in many header files:
error: expected ‘,’ or ‘...’ before ‘this’
All the lines that compiler is complaining somehow have this or delete keywords as parameter. See below:
int net_route(struct in_addr *dst, int delete);
or
extern int gad_new(struct gad_t **this)
Do you have any idea how can I fix this? Frankly, I have no idea what using 'this' or 'delete' mean as parameters. Are these only parameter names that gcc ignores the rule that we can not use keywords?
------------------------------
BTW, original programmer have used nested functions all across his code which were compiled fine using gcc. when I switch to g++, compiler complains about function-definition not being allowed in another function. Is there any way I can tell g++ to ignore this error?
Those weren't keywords in C, they are in C++.
You will have to rename those parameters before the code will compile in C++.
You may run into other porting issues related to C++'s stricter type checking before you are done.
Another option is to keep the C and C++ code in separate files, and use extern "C" in the C++ code for every function call that must cross the boundary. Since your C code extensively uses nested functions and other features not permitted in C++, this is probably your quickest approach.
this and delete are reserved keywords in C++ (not in C though) . You cannot use these as variable names when compiling with g++.
Its better to use different variable names in parameters and then compile with g++.

C++ : Unit testing using Google Mock with Code::Blocks, MinGW and C++11

I've been trying to learn unit testing on my own following along a book.
Code in the book use the C++11 standard and have a line like this:
auto variable = function(parameter);
When I first compiled it I got this warning:
warning: 'auto' changes meaning in C++11; please remove it [-Wc++0x-compat]
No biggie, I could fix that by checking the following box in the Project->Build options... menu:
[ ] Have g++ follow the C++ 11 ISO C++ language standard [-std=c++11]
Now, however, I get new errors related to Google Mock in the gtest-port.h :
| | In function 'int testing::internal::posix::StrCaseCmp(const char*, const char*)':
|1719| error: '_stricmp' was not declared in this scope
| | In function 'char* testing::internal::posix::StrDup(const char*)':
|1721| error: '_strdup' was not declared in this scope
| | In function 'FILE* testing::internal::posix::FDOpen(int, const char*)':|
|1779| error: 'fdopen' was not declared in this scope
Searching for this problem yielded little for me but I did try and define the target OS as it was a suggested solution in case it was not correctly identified automatically. Adding GTEST_OS_WINDOWS=1 and/or GTEST_OS_WINDOWS_DESKTOP=1 in the projects defines changed nothing.
I realize this is easily fixed in this instance by just providing the correct type instead of using auto but I'd like to find a solution for this if possible. Replacing auto and not having the -std=c++11 option checked makes the code work as intended so the library works.
I'm using Code::Blocks 13.12 , MinGW/g++ 4.8.1-4 and Google Mock 1.7 in Windows.
Thanks for reading =)
The answer here lies in the functions which are missing declarations: _stricmp, _strdup and fdopen. The first two are Microsoft versions of the POSIX functions stricmp and strdup. Note that you are specifying the use of the C++11 ISO standard which does not contain items in the POSIX standard. By specifying --std=gnu++11 you are telling the compiler to accept a hybrid of C++11 and POSIX along with GNU extensions.
Interestingly I cannot replicate this with GCC 4.8.2 on Linux so there is the possibility that something else is going on in the Google Mock headers when compiling on Windows.
Answering for anyone still facing the same issue:
The source of this issue might be in your CMakeLists file.
Set your compiler flags to -std=gnu++ instead of -std=c++
One way to do it would be to include
set(CMAKE_CXX_FLAGS "-std=gnu++0x")
to your CMakeLists file.

How to run program written for old compiler?

I'm looking for an implementation of Hybrid Tree(not important), and find an "old" one here.
The author said they have tried this code on the SUN Sparc platform (running Solaris 2.6) and with gcc-2.8.1 compiler. And my environment is gcc version 4.4.3 (Ubuntu 10.10).
The problem is:
I run "make" with the makefile he provides, but it gives me lots of error message as follows:
g++ -c Node.C
g++ -c DataNode.C
In file included from DataNode.h:18,
from DataNode.C:17:
Query.h:9:20: error: vector.h: No such file or directory
Query.h:10:19: error: stack.h: No such file or directory
Query.h:13:22: error: function.h: No such file or directory
Query.h:14:22: error: iostream.h: No such file or directory
DataNode.C:283:8: warning: extra tokens at end of #endif directive
In file included from DataNode.h:18,
from DataNode.C:17:
Query.h:29: warning: ‘typedef’ was ignored in this declaration
Query.h:44: warning: ‘typedef’ was ignored in this declaration
Query.h:86: error: expected initializer before ‘<’ token
Query.h:118: error: ISO C++ forbids declaration of ‘PQ’ with no type
Query.h:118: error: expected ‘;’ before ‘*’ token
Query.h:122: error: ISO C++ forbids declaration of ‘PQ’ with no type
Query.h:122: error: expected ‘;’ before ‘*’ token
Query.h:126: error: ISO C++ forbids declaration of ‘PQ’ with no type
Query.h:126: error: expected ‘;’ before ‘*’ token
Query.h:135: error: expected initializer before ‘<’ token
DataNode.C: In member function ‘void DataNode::DisconnectBranch(int)’:
DataNode.C:80: error: ‘memmove’ was not declared in this scope
make: *** [DataNode.o] Error 1
I know I need to modify the souce code so as to agree with the morden compiler, such as change vector.h to vector. But I find it's just endless.
So my question is: is there any convienent method to run this program, no matter automatically converting this code to "modern-style" or using a standalone "old-style" compiler ?
Any suggestions?
===Update:===
Thank you all, I installed gcc2.8.1 in a different dir using --prefix=/usr/local/gcc-2.8.1 and modify the "makefile" to use this old-version gcc(/usr/local/gcc-2.8.1/bin/gcc). But when I run "make", it still gives me errors of not finding the headers:
/usr/local/gcc-2.8.1/bin/gcc -c DataNode.C
In file included from DataNode.h:18,
from DataNode.C:17:
Query.h:9: vector.h: No such file or directory
Query.h:10: stack.h: No such file or directory
Query.h:11: deque: No such file or directory
Query.h:12: algorithm: No such file or directory
Query.h:13: function.h: No such file or directory
Query.h:14: iostream.h: No such file or directory
make: *** [DataNode.o] Error 1
Then I tried to find these heads in /usr/local/gcc-2.8.1 using find /usr/local/gcc-2.8.1 -name "*vector*", but got nothing.
So where are these heads for the old-version gcc?
You can make a vertor.h yourself which includes vector. This way you can fix the incompatibilities noninvasively.
Edit:
You may also need to add a
using namespace std;
in the header file(s). This is
generally a bad idea but this is one situation where i'd do it anyway.
Once you get it working i would reccomend rewriting it to use the new style header files and namespaces.
Debian Lenny (oldstable) has gcc 3.4. This might have a better backward compatibility. Try to make compatibility headers for the rest of the issues and include them via an extra -I directory, e.g. a vector.h header file that includes vector.
Do yourself the favor and try not to touch the old code. It is easy to break legacy code in unforeseen ways.
You could try running the program on QEMU which supports Solaris 2.6. The only problem might be hunting for the install disc/image. Also, there are people that sells old Solaris boxes on eBay for cheap, you might be able to grab one.
GCC provides download for very old versions, you might be able to get better chance if you try older version of the compiler.
gcc has -fpermissive option: try it and see whether at least some errors disappear. Also: try making a single header file that will include all requisite headers with using directives. For example, make stdinc.h containing:
#include <vector>
#include <iostream>
#include <stack>
...
using std::vector;
using std::fstream;
...
Replace all mentions of legacy C++ header files with a single include of stdinc.h. Old C++ didn't have namespaces, so even if you replace individual directives with just using namespace std;, clashes are unlikely.
If the only thing is
#include <vector.h>
to
#include <vector>
using namespace std;
Why not try sed?
grep for all includes to see if there are other includes than the c++ headers. If not your lucky.
Another thing that is more tricky is that there is old code that relies on accessing data through iterators in a non-standard way. I saw that in a Doom map editor for linux. Then you may need to do manual stuff.

G++ 4.4 compile error, lower versions works

I have my program written in C++ and it is can be successfully compiled on Ubuntu 9.04 with g++ 4.3.4 and Solaris OS with g++ 3.4.3. Now I have upgraded my Ubuntu to version 9.10 and g++ to version 4.4.1. Now compiler invokes the error in STL.
/usr/include/c++/4.4/bits/stl_deque.h: In member function ‘void std::deque<_Tp, _Alloc>::swap(std::deque<_Tp, _Alloc>&)’:
In file included from /usr/include/c++/4.4/deque:65,
/usr/include/c++/4.4/bits/stl_deque.h:1404: error: ‘swap’ is not a member of ‘std’
/usr/include/c++/4.4/bits/stl_deque.h:1405: error: ‘swap’ is not a member of ‘std’
/usr/include/c++/4.4/bits/stl_deque.h:1406: error: ‘swap’ is not a member of ‘std’
/usr/include/c++/4.4/bits/stl_deque.h:1407: error: ‘swap’ is not a member of ‘std’
I don't know how to fix it and if is possible that stl contains a bug. Can you help me, please?
Thanks a lot for all advices.
#include <algorithm>
In older versions of GCC, if you included any standard library header, that header would usually include many others. As mentioned by others, in your case <algorithm> got included this way.
This behavior isn't required by the standard. Many other implementations of the standard library don't exhibit this behavior, or to a lesser degree. It was just a design decision made by the GCC developers long ago. It seems they are now reducing this behavior, bringing it more in line with other implementations. This gives you more control over what gets included and what doesn't. Old code will break, but it's easily fixed by including the missing headers.
A post on an Apple forum suggests
#include <algorithm>