First of all, I made a simple program to test if compiling was working properly, it is as follows:
#include <iostream>
int main() {
std::cout << "Oi!";
}
Quite simple indeed, should compile properly, right? Wrong.
I am using MinGW for Windows 10, just to let you know.
I tried compiling it using "cpp <file name>.cpp -o a.exe" and was, first time, going through with the compile, but once I tried to execute the file it would send me this:
./a.exe: line 14: namespace: command not found
./a.exe: line 20: syntax error near unexpected token `('
./a.exe: line 20: ` typedef decltype(nullptr) nullptr_t;'
Clearly something was wrong, so I searched for a solution, found out someone had a similar problem and doing a reinstall solved it, so I went to the MinGW installation manager, noticed the C++ compiler library wasn't installed and installed it. It felt I was doing alright.
I also noticed that they were using g++ instead of cpp and tried that instead, it worked properly this time, but I would like to note that I have "git bash" installed, so I assume it used "git bash" 's command and not MinGW's.
So I opened cmd and tried using cpp, once I tried executing the program cmd said that the software wasn't compatible with the version of windows being executed, that doesn't sound right. I did a verbose compile with cpp and noticed this oddity:
#include <...> search starts here:
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/include/c++
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/include/c++/mingw32
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/include/c++/backward
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/include
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/../../../../include
c:\mingw\bin\../lib/gcc/mingw32/6.3.0/include-fixed
End of search list.
That doesn't follow Windows's file path standard...
Does it have anything to do with the problems I am facing? I just want things to compile! ;w;
As mentioned above, you need to use g++ to compile your code. Try the command g++ --version If you get any result that doesn't include a version number you need to install g++. Here is a guide that may be helpful.
https://techsupportwhale.com/install-gcc-compiler-on-windows/
Related
i just started to code in cpp and nothing is working idk if i didn't install the gcc properly or what but i already set the path of the bin file idk why it refuses to run
the code:
#include<iostream>
int main()
{
std::cout<<"hello";
}
and the problem is that when I try to use the "code runner extension" it is not working so I just press f5 and then when I get the error messages which says at first "could not find the task file'c/c++:g++.exe build active file' " and I get three options 1:debug anyway
2:configure task
3:cancel
when I choose debug anyway I get this error here
Since you're on windows consider installing Visual Studio or CLion. They're more beginner friendly - VSCode can get tricky to run c++ on windows. Either way, looks like you're trying to run your project without building it first. There should be a build option right next to the run option. Try building it, then running. The build is what compiles and creates the project.exe file, which is what the compiler is saying isn't there.
The referenced IDE's always auto-build on run, so there's that
If you're familiar with using the command line, these commands will do what you want, assuming the .cpp file is in your current directory.
g++ <FILENAME>
./a.out
There are wonderful flags you can add to the first command (the compiling command) like -Wall, -Wextra, -o, and many more. But, since it seems like you're just starting out, there's no need to worry about those!
If you're not familiar with the command line, I would encourage you to become familiar! It is an extremely powerful tool for a programmer. Here is a YouTube video that talks about it.
I am trying to compile the following program:
#include <iostream>
int main(){
std::cout << "Hello, world!";
return 0;
}
When I compile it, I get this message:
C:\programs>g++ test.cpp
Info: resolving std::cout by linking to __imp___ZSt4cout (auto-import)
c:/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../../mingw32/bin/ld.exe: warning: a
uto-importing has been activated without --enable-auto-import specified on the c
ommand line.
This should work unless it involves constant data structures referencing symbols
from auto-imported DLLs.
The build succeeds and the executable runs as expected, but this warning still irritates me. I expect a successful build to be completely silent. This message gives the false impression that there's something wrong with my code.
I can silence this error with g++ -Xlinker --enable-auto-import test.cpp, but this is undesirable, as it triples the number of characters I need to type to compile a program.
Questions:
Why does this warning appear for the simplest of programs? i don't expect cryptic warnings when I compile Hello World.
Is it possible to silence this warning without passing the flag to the linker every time? An option in a config file hidden somewhere in c:\mingw, perhaps? Or maybe I missed an "automatically enable auto-import" checkbox during installation?
Possibly Relevant Specs
GCC Version 4.5.0
ld.exe Version 2.20.51.20100613
Windows XP Service Pack 3
I used to face same problem as you do with g++. I solved this irritating problem just now. Here is how I come to the solution, step-by-step:
On Windows, you can create an alias of g++ with all given options which you want to use with g++. Say, for example, you want to create an alias s++ of g++ -enable-auto-import, then you run this on cmd as:
C:\>doskey s++=g++ -enable-auto-import
This creates an alias called s++. But this alias will not take any command line argument, which means, you cannot write this:
C:\>s++ filename.cpp //it is not working
To make it work, if you've to tell the alias to accept command line arguments while creating it, so here is how it is done:
C:\>doskey s++=g++ -enable-auto-import $*
Please note the $* at the right, which indicates that now s++ can take command line argument:
C:\>s++ filename.cpp //yayyyy..its working now, without giving any warnings!
But you may not prefer to create the alias everytime you open cmd. In that case, you can create a shortcut of cmd.
For example, I created a shortcut called Console and in the Target textbox of shortcut window, I wrote this:
C:\WINDOWS\System32\cmd.exe /K doskey s++=g++ -enable-auto-import $*
And since this is too long (horizontally), one screenshot was not able to capture the entire command. I took two screenshots so that you could see yourself how I did it:
Left part of the command
Right part of the command
For more information on creating aliases on windows, see this:
Creating aliases on Windows
I did some reading and it looks like it might be related to the mingw32 dll not having dllimport attributes defined.
Perhaps there is a patch or you can rebuild mingw32 yourself and add them?
I'm trying to get a basic example running using SWIG to convert a C++ file into Ruby. I have Ruby 2.0.0p451 (64 bit version) installed and I've also installed the 64-bit DevKit. I'm running Windows 7 and trying to use swigwin-2.0.12. Finally, I am using the GCC C++ compiler supplied by Mingw-builds for the 64-bit version of Windows.
I have the basic C++ hello world program as shown below.
#include <iostream>
#include <cstdlib>
using namespace std;
main()
{
cout << "Hello World!";
system("pause");
return 0;
}
At the command prompt, I use the command:
swig -module -c++ -ruby hello_world.cpp
This completes fine and produces a file titled hello_world_wrap.cxx. However, when I receive an error when I try to compile the .cxx file using the command:
g++ -fPIC -c hello_world_wrap.cxx -IC:\Ruby200-x64\include\ruby-2.0.0
The error I am receiving is:
All the research I've done has pointed me to an installation of the incorrect DevKit, but I don't think this is my issue. I've made sure to download the 64-bit version of Ruby and the DevKit. I've checked the folder specified in the error, and there is no config.h file. I'm not sure why the config.h file does not exist or why ruby.h is trying to load it.
Any thoughts?
Check that C:\Ruby200-x64\include\ruby-2.0.0\ruby\config.h exists. If not, find it and fix the path.
Update:
Check if there is a ruby.h in the same folder. If there is then just use -IC:\Ruby200-x64\include\ruby-2.0.0\ruby\x64-mingw instead. Otherwise try adding a second -I, for this extra path. I agree with you this is a little strange (not so much the former, but definitely if you have to have two -I). The script at https://groups.google.com/forum/m/#!topic/comp.lang.ruby/RpjuvXpFI30 suggests that this might be normal, I.e. you need one -I for platform-independent headers and one for platform-dependent.
I'm trying to compile an run a very basic program given below (test.cpp) which calls the OpenNI class. You can see the files and dirs they're in here. Sorry that some characters screws up a little bit in the browser's encoding. I'm using the linux command: tree, if you know a better command tell me and I will update it.
File Structure
I'm following the guide here, see "GCC / GNU Make".
#include < stdio.h >
#include < OpenNI.h >
using namespace openni;
int
main ( void )
{
Status rc = OpenNI::initialize();
if (rc != STATUS_OK)
{
printf("\nInitialize failed\n%s\n", OpenNI::getExtendedError());
return 1;
}
printf("Hello, world!\n");
return 0;
}
Here is what I'm running in the command line to compile it (gcc 4.7.2):
gcc test.cpp -I../OpenNI-2.0.0/Include -L/home/evan/Code/OpenNi/Init -l OpenNI2 -o test
This works fine but when I run ./test I get the following error:
Initialize failed
DeviceDriver: library handle is invalid for file libOniFile.so
Couldn't understand file 'libOniFile.so' as a device driver
DeviceDriver: library handle is invalid for file libPS1080.so
Couldn't understand file 'libPS1080.so' as a device driver
Found no valid drivers in './OpenNI2/Drivers'
Thanks, any help would be much appreciated.
Instructions from your guide says, that
It is highly suggested to also add the "-Wl,-rpath ./" to your linkage command. Otherwise, the runtime linker will not find the libOpenNI.so file when you run your application. (default Linux behavior is to look for shared objects only in /lib and /usr/lib).
It seems you have exactly this problem -- it can not find some libraries. Try to add proper rpath (seems to be /home/evan/Code/OpenNi/Init/OpenNI2/Drivers in your case) to your compilation string.
I had the same issue after compiling this little "Hello World" with Eclipse and trying to run it in the command line.
The "Wl,-rpath=./" thing did not work for me.
As also discussed here it worked for me after setting some env. variables before execution:
export LD_LIBRARY_PATH="/path/to/OpenNI2:$LD_LIBRARY_PATH"
export OPENNI2_DRIVERS_PATH="/path/to/OpenNI2/Drivers"
export LD_LIBRARY_PATH="/path/to/OpenNI2/Drivers:$LD_LIBRARY_PATH"
Somewhere I got the info that the first two lines should be enough but it was the third line which is important. I does also work just with the third line.
Currently I'm trying to start programming on my new Mac. I installed TextWrangler, and chose C++ as my language of choice; since I have some prior knowledge of it, from when I used Windows.
So, I wrote the ever so common "Hello World" program. Although, when I tried to run it, I got an error:
"This file doesn’t appear to contain a valid ‘shebang’ line (application error code: 13304)"
I tried searching the error code to find out how to fix this, but I couldn't find anything.. I have no idea what a 'shebang' line is... Can someone help me out?
You need to compile it with a compiler first. I assume you tried to run the source file like ./source but C++ doesn't work this way.
With some compilers however, you can provide a shebang-line as the first line of the source file (the #! is known as shebang or crunchbang, hence the name), like so:
#!/path/to/compiler
So that the shell knows what application is used to run that sort of file, and when you attempt to run the source file by itself, the compiler will compile and run it for you. That's a compiler-dependent feature though, so I recommend just plain compiling with G++ or whatever Macs use to get an executable, then run that.
While I wouldn't recommend it for regular C++ development, I'm using a simple shell script wrapper for small C++ utilities. Here is a Hello World example:
#if 0 // -- build and run wrapper script for C++ ------------------------------
TMP=$(mktemp -d)
c++ -o ${TMP}/a.out ${0} && ${TMP}/a.out ${#:1} ; RV=${?}
rm -rf ${TMP}
exit ${RV}
#endif // ----------------------------------------------------------------------
#include <iostream>
int main(int argc, char *argv[])
{
std::cout << "Hello world" << std::endl;
return 0;
}
It does appear that you are trying to run the source file directly, however you will need to compile using a C++ compiler, such as that included in the gcc (GNU Compiler Collection) which contains the C++ compiler g++ for the Mac. It is not included with the Mac, you have to download it first:
from http://www.tech-recipes.com/rx/726/mac-os-x-install-gcc-compiler/ : "To install the gcc compiler, download the xcode package from http://connect.apple.com/. You’ll need to register for an Apple Developer Connection account. Once you’ve registered, login and click Download Software and then Developer Tools. Find the Download link next to Xcode Tools (version) – CD Image and click it!"
Once it's installed, if you are going for a quick Hello World, then, from a terminal window in the directory of your source file, you can execute the command g++ HelloWorld.cpp -o HelloWorld. Then you should be able to run it as ./HelloWorld.
Also, if you're coming from a Visual Studio world, you might want to give Mono and MonoDevelop a try. Mono is a free implementation of C# (and other languages), and MonoDevelop is an IDE which is very similar to Visual Studio. MonoDevelop supports C# and other .NET languages, including Visual Basic .NET, as well as C/C++ development. I have not used it extensively, but it does seem to be very similar to VS, so you won't have to learn new everything all in a day. I also have used KDevelop, which I liked a lot while I was using it, although that's been a while now. It has a lot of support for GNU-style development in C/C++, and was very powerful as I recall.
Good luck with your endeavors!
Links:
Mono: http://mono-project.com/Main_Page
MonoDevelop: http://monodevelop.com/
KDevelop: http://kdevelop.org/
shebang is http://en.wikipedia.org/wiki/Shebang_%28Unix%29.
not sure why your program is not running. you will need to compile and link to make an executable.
What I find confusing (/interesting) is C++ program giving "Shebang line" error. Shebang line is a way for the Unix like operating system to specify which program should be used to interpret the rest of the file. The shebang line usually points to the path of the interpreter. C++ is a compiled language and does not have interpreter for it.
To get the real technical details of how shebang lines work, do a man execve and get that man page online here - man execve.
If you're on a mac then doing something like this on the commandline:
g++ -o program program.cpp
Will compile and link your program into an executable called program. Then you can run it like:
./program
The reason you got the 'shebang' error is probably because you tried to run the cpp file like:
./program.cpp
And the shell tries to find an interpreter to run the code in the file. Because this is C++ there is no relevant interpreter but if your file contains Python or Bash then having a line like this
#!/usr/bin/python
at the 1st line in your source file will tell the shell to use the python interpreter
The lines that start with a pattern like this: #!/.../.../.. is called a shebang line. In other words, a shebang is the character sequence consisting of the characters number sign and exclamation mark (#!).In Unix-like operating systems, when a text file with a shebang is used as if it is an executable, the program loader mechanism parses the rest of the file's initial line as an interpreter directive. The loader executes the specified interpreter program, passing to it as an argument the path that was initially used when attempting to run the script, so that the program may use the file as input data.