Now I'm trying to install RealPlexor by dklab, but it's falls with errors:
# bash ./Make.sh
In file included from dklab_realplexor.cpp:68:
utils/misc.h: In function ‘void die(std::string)’:
utils/misc.h:105: error: expected primary-expression before ‘[’ token
compilation terminated due to -Wfatal-errors.
Here is that line
s = regex_replace(s, regex("\\$!"), [](smatch s) { return strerrno(); });
Make sure that you are passing the following flag to your compiler (as described in the the g++ documentation):
-std=c++11
This tells the gcc compiler (g++) to compile your code with C++11 semantics.
The lambda expression syntax you are using (the part starting with []) is a C++11 feature, and will cause compilers great confusion if it appears in code that they aren't expecting to be C++11.
However, as has been pointed out in another comment here (and is confirmed by this table, the version of gcc you are running (4.4.5, per a comment) doesn't have lambda expression support. May have to use a function object instead, or upgrade to a newer version of gcc/g++.
Just say
s = regex_replace(s, regex("\\$!"), *(smatch s) { return strerrno(); });
The [] operator is usually used to index something (like a character array), so C++ expects something in front of it
Also try this suggestion from #DavidO:
You're using a lambda expression which is a C++11 syntax, but probably haven't set your compiler to recognize C++11. If you're using g++, you would use the -std=c++11 flag.
Related
The error that is being generated is below.
error: 'size' was not declared in this scope
When I use nums.size(), it is working fine. It could be because of using an older compiler version, but in my system when I check the version it shows 10.3.0, which I think is the latest version. How do I fix this?
The std::size function was added in C++17, therefore, you need to enable its support. With GCC, just add -std=c++17 as a command-line argument to your g++ call.
You can also check the libstdc++ source code: https://github.com/gcc-mirror/gcc/blob/master/libstdc%2B%2B-v3/include/bits/range_access.h#L236. As you can see, there is an #ifdef that makes std::size available only if C++17 (or higher standard) support is applied.
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++.
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.
I am developing a program in C++ on Linux. The gcc version is 4.5.1 20100924. I want to use std::atomic_int in my program. I have included atomic header as below:
include <atomic>
When I compile the program I get below errors:
In file included from /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomic_base.h:87:0,
from /usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/atomic:41,
from ../Source/Main.h:33:
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:107:25: error: ‘char16_t’ was not declared in this scope
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:107:33: error: template argument 1 is invalid
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:107:53: error: invalid type in declaration before ‘;’ token
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:110:25: error: ‘char32_t’ was not declared in this scope
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:110:33: error: template argument 1 is invalid
/usr/lib/gcc/x86_64-redhat-linux/4.5.1/../../../../include/c++/4.5.1/bits/atomicfwd_cxx.h:110:53: error: invalid type in declaration before ‘;’ token
If I include <cstdint>, I get the same errors. The headers uchar.h and cuchar.h are not there on my system. How can I resolve the compilation errors?
Thank you in advance.
EDITED:
I was wrong about that. just pass --std=c++0x to g++, and that would do it.
You seem to not have enabled C++11 support in your compiler or you use a compiler that has these new types not declared.
For char16_t and char32_t, you need no extra include.
g++ howto:
Type g++ --version. If it is at least 4.4, then it has support for new string literals. If not: You need a newer compiler version.
Then, make sure to pass --std=c++0x or --std=c++11 to the compiler.
For some reason gcc does not like when template parameter is a global namespace symbol, i.e.
TemplateClass<::GlobalSymbol>
It works when I do
TemplateClass< ::GlobalSymbol>
That is, gcc does not like to see <::
Is it possible to prevent without modifying sources (which are autogenerated)?
UPD: I don't want to modify sources. I found that -fpermissive seems to change this to a warning instead of error, but haven't found yet how to enable it from code (using pragmas for example).
UPD: Well, I found that
#pragma GCC diagnostic ignored "-fpermissive"
does the trick, anyway I accept the answer that helped me to find this out.
<: is a digraph which is equivalent to [, thus the error. Since you don't want to modify the code a workaround is to use -fpermissive command-line argument or pragma to G++ (it actually gives you a hint):
test.cpp:9:16: note: (if you use ‘-fpermissive’ G++ will accept your code)
With gcc 4.6 I get the following error:
graphs.cpp: In function ‘int main()’:
graphs.cpp:9:15: error: ‘<::’ cannot begin a template-argument list [-fpermissive]
graphs.cpp:9:15: note: ‘<:’ is an alternate spelling for ‘[’. Insert whitespace between ‘<’ and ‘::’
graphs.cpp:9:15: note: (if you use ‘-fpermissive’ G++ will accept your code)
So, -fpermissive is the way to go. [EDIT: I see now that you added that you already found this]
Else, since you mentioned that the sources are auto-generated, you could add a post processing step. For example using sed
sed -i 's,<::,< ::,g' filename.cpp
or something similar in e.g. python. But only if you are sure you never use <:: for something else.