expected unqualified-id before token... 'std::' - c++

When i compile C++ code in an Android NDK project i get:
expected unqualified-id before '(' token FPEnvironment_DUMMY.h /PocoFoundation/jni/include/Poco line 98 C/C++ Problem
The error origins from the lines:
inline bool FPEnvironmentImpl::isInfiniteImpl(double value)
{
return std::isinf(value) != 0;
}
The following packet is included:
#include <cmath>
It seems that the error disappear when i remove std::, why does this happen?
I have to many source files to remove the class name std in all of them :/

So the solution i found is :
remove std:: from the header-files signalled by the errors when building according to this
Since we next were going to include the static lib we built here in an eclipse-Android project the new compilation required std:: in the headers again so we simply reverted them back to their original style std::isinf etc. The usage of std:: depends on what stdlibrary you use, gnu or stdl_port..
The issue is discussed here

Related

Compile error inside boost: "use of undefined type 'boost::mpl::bool_<true>"

I am getting this strange error when compiling a large CPP file, at this line:
#include <boost/regex/v4/regex.hpp>
Error C2027 use of undefined type
'boost::mpl::bool_'
C:\github\microsoft\vcpkg\installed\x86-windows\include\boost\regex\v4\basic_regex_parser.hpp 59
In bool_fwd.hpp I see:
typedef bool_<true> true_;
typedef bool_<false> false_;
In basic_regex_parser.hpp this is the line generating the error:
inline boost::intmax_t umax()
{
return umax(mpl::bool_<std::numeric_limits<boost::intmax_t>::digits >= std::numeric_limits<std::size_t>::digits>());
}
It appears basic_regex_parser.hpp isn't including bool_fwd.hpp but diving into these files I am lost what's wrong.
I've moved that #include to be right at the top of my stdafx.h file so it's before any other headers, and get the same result. We've recently switched from manually building boost 1.68 => 1.76 via vcpkg but I don't know which if either is the cause. We also switched to C++17 and I note boost has a dependency on std::numeric_limits, could this is the issue?
This isn't supported, see same issue in https://github.com/boostorg/regex/issues/145

Error: expected initializer before ': ' token , gcc compiler

I encounter this error when I am trying to compile a c++ code via a Makefile.
error: expected initializer before ':' token
I have checked the compatibility of the compiler of my system
I also checked the paths etc. I also did some test; such as adding a semicolon after the 2nd declaration of class but didnt work. I have little to no experience with c++, the script is not even written by me; it is part of vtk library (Visualisation toolkit). Part of the script from where
the error generates is:
#ifndef __vtkProcessObject_h
#define __vtkProcessObject_h
#include "vtkAlgorithm.h"
class vtkDataObject;
class VTK_FILTERING_EXPORT vtkProcessObject : public vtkAlgorithm
{
public:
vtkTypeRevisionMacro(vtkProcessObject,vtkAlgorithm);
void PrintSelf(ostream& os, vtkIndent indent);
I get the error in line 8.
Probably it is something really straightforward, but as I said I have no clue how this language works.
The VTK_FILTERING_EXPORT macro is defined in a header, and is largely there for Windows and/or GCC symbol visibility. You don't mention what version of VTK you are compiling, but using CMake to generate the Makefiles would ensure the correct include paths are set up. If this is Linux, and the GCC visibility functionality has not been activated you could define the macro to nothing, but I suspect you would hit many other issues once you got past this point in the compilation.

What can cause ambiguous symbol errors on one computer and not another?

I'm using Visual Studio 2010 to work on C++ code. The project and all its contents have been written by someone else, and copied onto a shared drive. When the creator builds it on his computer, it works fine. When I try to build the solution, I get a whole bunch of these errors
error C2872: '<lambda0>' : ambiguous symbol could be
'[File].cpp(66) : anonymous-namespace'::<lambda0>' or
'[Different file].h(549) : `anonymous-namespace'::<lambda0>'.
Here's an example of a line which is said to be in error:
std::pair<int, std::pair<int, Point>> b) -> bool { return (a.second.second < b.second.second ); });
It seems like the error always occurs with a line which ends in '});'. The full code is rather enormous to show here, and it works on other computers, so presumably it's a problem with my settings or something. Can anybody hazard a guess as to what they may be?
Not sure if you've seen this or not but according to MSDN page for that compiler error:
C2872 can occur if a header file includes a using Directive (C++), and a subsequent header file is #include'd and contains a type that is also in the namespace specified in the using directive. Specify a using directive only after all your header files are specified with #include.
MSDN Page
I have had the same issue withe ambiguous symbol problem. For me, it turns out that I was using two namespaces which have the same function but obviously different definitions. I have to stop using one of the namespaces and this solve the issue.
As an example:
using namespace cv;
using namespace boost::accumulator;
accumulator_set<double, stats<tag::mean, tag::variance> > acc;
double meanval = mean (acc);
This will through a compilation error: error C2872: 'mean' : ambiguous symbol This is because both namespaces cv and boost::accumulator have the same function "mean"
I hope this helps
I have had the same issue
Installing VS2010 SP1 fixed the ambiguous anonymous-namespace'::<lambda0> issue for me. VS2010 without the SP1 has problems with lambdas.

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.

Strange error when adding #include <string>

I have the following very simple application that compiles and runs fine:
EDIT: changed the example to be simpilar to end confusion of the real issue
int main() {
return 0;
}
As soon as I add #include <string> (and not even reference std::string), it fails to compile and I get the following error:
/usr/include/c++/4.1.2/bits/allocator.h:82 error: expected template-name before '<' token
Along with about 456 other, similar errors.
Any ideas? Thanks!
UPDATE:
Line 82 of /usr/include/c++/4.1.2/bits/allocator.h references the template __glibcxx_base_allocator at the location of the error. That template is defined in bits/c++allocator.h. When I search the system for that file, I get 3 hits, but none of them are in /usr/include/c++/4.1.2/bits/ as one would expect.
I have version 3.1.6, 4.1.1, and 4.3.2, but not 4.1.2 as the rest of the includes I am using. I am not sure which one is being used (if any, however, I don't get any error for an unknown file), but it seems the problem may stem from this.
The problem appears to be the installed development packages are not correct or incomplete (not to be confused with corrupt). Forcing g++ to use different include versions corrects that:
g++ -nostdic++ hello.cc -o hello -I/usr/include/c++/3.4.6
All the alternative directories (4.1.1, 4.1.2 and 4.3.2) are incomplete causing inappropriate files to be included causing the unusually errors. For example:
/usr/include/c++/4.1.2/bits/allocator.h requires __glibcxx_base_allocator located in bits/c++allocator.h which is being included from either /usr/include/c++/4.1.1 or /usr/include/c++/4.3.2 and appear to be incompatible. Forcing the compiler to use the only complete set of includes rectifies this.
Almost certainly g++ is detecting .cc as a C source file, not C++ and passes it through to gcc instead of compiling as C++. You can easily test by renaming your file to hello.C. There's also a language parameter to g++ you can use.
EDIT: This seems to work fine in g++ 4.2 with a .cc extension so that might not be it. Do you have any other headers included you aren't showing us? They could be interfering with <string>.
EDIT2: Alternatively your headers might not be set up right. Does this work:
#include <string>
int main()
{
return 0;
}
Errors like this have been heard of to occur when the C++ standard library headers are corrupted/not fully installed – maybe there is even a message referring to a missing include among your 456 other errors.
In any case, make sure that libstdc++-devel, resp. the package containing the C++ standard library header files of your distribution, is properly installed.
Check your include path. The paths can be specified as environment variables or specified on the command line. You could be using an include file from a different compiler or different version of the same compiler.
Also, try using <cstdio> rather than <stdio.h>.
Another suggestion: change <> to "".
This could be error caused at preprocess stage. Just preprocess your cpp file by passing flag -E to gcc and Look at the place the compiler complains.