i have redhat with gcc 4.1.1 i have compile as "gcc test.c" and give the following error
Error : expected '=' ,',' , ';' , ásm' or '__ attribute__' before '<' token
the code in "test.c" is as follow
template <typename T> class A {
public:
T foo;
};
Compile with g++ and/or rename your file to test.cpp.
If you compile with gcc test.c then your file will be assumed as a C file. There's no templates in C.
This is C++ code, not C. You need to use g++, i.e. g++ test.c. Also, to avoid confusion, you should rename your file to end with .cpp or .cxx.
From the GCC Manual, compiling a file with the .c extension will compile your code as though it were C, not C++. The easiest solution is to compile your code with g++ instead. The g++ command sets the default language to C++ and automatically links your code against the C++ standard library. You can do both of those with gcc but you have to do it by hand. Exactly how you do that is left as an exercise. :-)
Related
I just tried to compile simple Hello World in C++ using MinGW compiler in my Windows 10 command line. I used the command gcc main.cpp, and as I hit enter, I got this error: 'main.cpp:1: No include path in which to find iostream'.
What is the error and how do I fix it?
Use g++ main.cpp
The command gcc is setup for c compilation. It does not link the c++ standard library.
g++ does link c++ standard library.
Earlier, I posed a related question.
I have the following program extracted from a large project in my Mac OS
#include <iostream>
int main(){
std::cout<<"hello"<<std::endl;
return 0;
}
Compiling it with Clang fails with the following error:
$ clang test.cpp
test.cpp:1:10: fatal error: 'iostream' file not found
#include <iostream>
^
1 error generated.
For information,
A) I have already installed xcode command line tools, using xcodeselect --install. But it seems iostream does not locate in the default search path of clang.
B) Using g++ instead of clang compiles the program. But in my problem, I am not allowed to use other compiler than clang, or to change the source program.
C) I can see workaround techniques, e.g, by tweaking the search path in .bashrc or with some symbolic link, etc. But I feel reluctant to use them, because it seems that I have an installation problem with my Clang and tweaking the path only helps to avoid one of these path issues.
clang and clang++ do different things. If you want to compile C++ code, you need to use clang++
Alternatively you can invoke c++ compiler directly by providing language name explicitely:
clang -x=c++
in my test.cu file (cu file item type is CUDA C/C++)
__global__ void foo()
{
}
void CudaMain()
{
foo<<<1,1>>>();
}
and in my test.cpp file
#include "mycuda.cu"
int main()
{
CudaMain();
return 0;
}
and compilator send me error "error c2059 syntax error ' <' " in test.cu file
Inclusion of CUDA source files in a C++ file doesn't work because this simply makes the CUDA source part of the C++ program code and regular C++ compilers do not understand CUDA syntax extensions. If you still want to keep your CUDA code separate from the non-CUDA C++ code, then you might want to look into separate compilation. CUDA source code can be compiled to regular object files, that can then be linked with other object files to produce an executable.
Modify the C++ code to read:
extern void CudaMain(void);
int main()
{
CudaMain();
return 0;
}
Compile the CUDA file with nvcc, the C++ code with your C++ compiler and then link the resulting object files with nvcc (you may also need to specify the standard C++ library in the link command):
$ nvcc -c -o test_cuda.o test.cu
$ g++ -c -o test_cpp.o test.cpp
$ nvcc -o test.exe test_cuda.o test_cpp.o -lstdc++
Edit: your question is about VS2010. May be you have to create custom build steps there.
Based on the thread here: https://forums.developer.nvidia.com/t/cuda-build-error/52615/4
Your test file extension should be .cu as well, but if you're using MSCV rename does not enough you should create a new CUDA C/C++ source module in your VS project.
Also you should put spaces between the <> operators like.
foo< < <1,1> > >();
Because C++ cannot parse the <<<>>>.
I know this is an old question but I was searching around and it jogged my memory for a solution that hasn't been mentioned.
The nvcc help offers:
--x {c|c++|cu} (-x)
Explicitly specify the language for the input files, rather than letting
the compiler choose a default based on the file name suffix.
Allowed values for this option: 'c','c++','cu'.
So although it's a bit of a blunt tool, you can do:
nvcc my_source.cpp -x cu ...
and it'll compile the .cpp as if it was named .cu (ie as CUDA).
I know this topic was few times there, but I can't get satisfactory answer.
C:\Users\Krzysiek>gcc test.c
test.c:3:20: fatal error: iostream: No such file or directory
compilation terminated.
This is what I try to do
#include <iostream>
using namespace std;
int main ()
{
cout << "Hello World!";
return 0;
}
Simple program with "include"
I've heard of LIBRARY_PATH. So I've setted that. Still this same error I have.
GCC provides wrappers around calling its various compilers.
You are using gcc, which is for C (and consequently will not include or link the C++ standard library; the compiler would go on to complain about the rest of your code, too, since it's not valid C);
Use g++, which is for C++.
Also try to use a conventional extension for C++ source files, which is .cc, .cxx or .cpp.
Use g++ instead: it will link to the c++ standard library.
When you use the gcc command, gcc looks at the file extension to decide which language to use to compile. As you used a .c file, gcc will switch by default to C.
# Use the C compiler
gcc test.c
# Use the C++ compiler
gcc test.cpp
To choose a different language, you can use the -x option:
# Use the C++ compiler even if the extension is .c
gcc -xc++ test.c
Another method of using the C++ compiler is to use g++ in the command line. This is the preferred way, as it links with the correct libraries.
# Use the C++ compiler
g++ test.c
How can I compile a C++ program with the GCC compiler?
File info.c
#include<iostream>
using std::cout;
using std::endl;
int main()
{
#ifdef __cplusplus
cout << "C++ compiler in use and version is " << __cplusplus << endl;
#endif
cout <<"Version is " << __STDC_VERSION__ << endl;
cout << "Hi" << __FILE__ << __LINE__ << endl;
}
And when I try to compile info.c:
gcc info.C
Undefined first referenced
symbol in file
cout /var/tmp/ccPxLN2a.o
endl(ostream &) /var/tmp/ccPxLN2a.o
ostream::operator<<(ostream &(*)(ostream &))/var/tmp/ccPxLN2a.o
ostream::operator<<(int) /var/tmp/ccPxLN2a.o
ostream::operator<<(long) /var/tmp/ccPxLN2a.o
ostream::operator<<(char const *) /var/tmp/ccPxLN2a.o
ld: fatal: Symbol referencing errors. No output written to a.out
collect2: ld returned 1 exit status
Isn't the GCC compiler capable of compiling C++ programs?
On a related note, what is the difference between gcc and g++?
gcc can actually compile C++ code just fine. The errors you received are linker errors, not compiler errors.
Odds are that if you change the compilation line to be this:
gcc info.C -lstdc++
which makes it link to the standard C++ library, then it will work just fine.
However, you should just make your life easier and use g++.
Rup says it best in his comment to another answer:
[...] gcc will
select the correct back-end compiler
based on file extension (i.e. will
compile a .c as C and a .cc as C++)
and links binaries against just the
standard C and GCC helper libraries by
default regardless of input languages;
g++ will also select the correct
back-end based on extension except
that I think it compiles all C source
as C++ instead (i.e. it compiles both
.c and .cc as C++) and it includes
libstdc++ in its link step regardless
of input languages.
If you give the code a .c extension the compiler thinks it is C code, not C++. And the C++ compiler driver is called g++, if you use the gcc driver you will have linker problems, as the standard C++ libraries will not be linked by default. So you want:
g++ myprog.cpp
And do not even consider using an uppercase .C extension, unless you never want to port your code, and are prepared to be hated by those you work with.
You should use g++ instead of gcc.
By default, gcc selects the language based on the file extension, but you can force gcc to select a different language backend with the -x option thus:
gcc -x c++
More options are detailed on the gcc man page under "Options controlling the kind of output". See e.g. gcc(1) - Linux man page (search on the page for the text -x language).
This facility is very useful in cases where gcc can't guess the language using a file extension, for example if you're generating code and feeding it to gcc via standard input.
The difference between gcc and g++ are:
gcc | g++
compiles C source | compiles C++ source
Use g++ instead of gcc to compile you C++ source.
If I recall correctly, gcc determines the filetype from the suffix. So, make it foo.cc and it should work.
And, to answer your other question, that is the difference between "gcc" and "g++". gcc is a frontend that chooses the correct compiler.
An update with my GCC version 10.3.0 on Ubuntu. Even if I add -lstdc++ or use the correct extension, cc1plus must be installed on the system. Otherwise this error shows up:
gcc: fatal error: cannot execute ‘cc1plus’: execvp: No such file or directory
One way to get this is to install g++ even if you're not going to use it directly, e.g. sudo apt install g++.
Now, if I use the extension .cc, I can just call gcc directly, however, warnings and errors still show up. To use gcc cleanly, with a .c extension I have to call it like this:
gcc -x c++ info.c -lstdc++
Shorter if I use the .cc extension, like the accepted answer:
gcc info.cc -lstdc++
Or like others have said, just use g++ info.c instead. No extra parameters are needed to indicate C++, and it works with .c, .cc and .cpp extensions.
It worked well for me. Just one line code on the Windows command line (CMD).
First, confirm that you have installed gcc (for C) or g++ (for C++) compiler.
On the command line, for gcc, type:
gcc --version
On the command line, for g++, type:
g++ --version
If it is installed then proceed.
Now, compile your .c or .cpp using the command line.
For C syntax:
gcc -o exe_filename yourfilename.c
Example:
gcc -o myfile myfile.c
Here exe_filename (myfile in example) is the name of your .exe file which you want to produce after compilation (Note: I have not put any extension here). And yourfilename.c (myfile.c in example) is the your source file which has the .c extension.
Now go to the folder containing your .c file. Here you will find a file with the .exe extension. Just open it. Hurray...
For C++ syntax:
g++ -o exe_filename yourfilename.cpp
After it, the process is the same as for the C syntax.
For a .cpp File:
g++ myprog.cpp -o myprog