I'm working with a very peculiar environment: SH4 architecture, RedHat Linux, kernel 2.4.5.
I'm trying to write a graphic application using Xlib that can run in this environment.
I experimented long time ago with cross-compiling for SH4 architecture and it worked OK. However I never had to compile for a specific outdated kernel.
Set up a VM with linux mint, installed g++, cmake,
#include <iostream>
using namespace std;
int main()
{
//print output
cout << "hello" << endl;
return 0;
}
I run the compiler
g++ hello.cpp
And get a binary file "a.out".
I can execute the binary by typing "./a.out". It prints "hello".
However when I transfer "a.out" to the SH4 machine via FTP and try to run it I get:
bash: a.out: cannot execute binary file
This leads me to believe that the target computer doesn't understand the compiled binary.
Related
My problem is when debugging from Eclipse a program that uses Boost (even pure header) then the GDB debugger is unable to locate frame base for the function being trace into.
Please note that except this, the program works like a charm in debug and release mode. The problem is only for debugging and inspecting source code refering to Boost.
Please not also that the problem only affects OSX Yosemit.
The issue is that I can't see the value of the local variables. Below is the message I have in the "(x)= Variables" window of Eclipse :
Failed to execute MI command:
-data-evaluate-expression result
Error message from debugger back end:
Could not find the frame base for "main()".
The code is as simple as :
#include <boost/regex.hpp>
#include <iostream>
int main() {
int result = 1;
boost::regex reExpression("[a-z]+");
std::cout << "!!!Hello World !!!" << std::endl;
result ++;
cout << " Result = " << result << "\n";
return result;
}
The program is compiled using the command :
g++ -v -o -g bin/Essai-MACOS-Debug src/Essai.cpp -I/opt/local/include /opt/local/lib/libboost_regex-mt.a
If you remove the reference to Boost.Regex then everything is ok. I can inspect the value of the local variable result.
More interesting: I built a library with a single function relying on Boost, and call that function from main(). It happens that can inspect the code in main() and have the value of main's local variable but when I came inside the library's function, the one now referring to boost then again I can't see the local variables of that function.
So it seems that as soon as a source file is referring to Boost, GDB get confused.
I have installed GCC 4.9, GDB 7.7 and Boost 1.57 using MacPort on OSX Yosemit.
I've compile Boost from source with MacPort in order to use GCC instead of GCC using the command :
sudo port install -ns boost config.compiler=macport-gcc-4.9
I also tried with a version of Boost I compiled myself and I did have the same issue.
Does anyone knows about this problem ?
EDIT:
I've compiled and installed the last GDB version from sources (7.9) and have the same issue described here than with the 7.7.1 provided by MacPorts.
all.
Compiling simple stuff using the gcc toolchain for several years, today I ran against a curious phenomenon.
I installed Kubuntu 14.04 to a common desktop i686 machine with gcc 4.8.2 in it. But then, trying to build some well coded stuff pulled out from my local repository, I ran against tons of 'undefined reference to' messages. The code compiles, links und runs well under Ubuntu 11.04 / gcc 4.5.2.
I checked the linking process (by -Wl,--verbose to gcc), think it works. It finds all libraries I specify in the link command. An objdump -t myLib.so brings exactly the symbols I'd expect - but the linker doesn't see them.
Checking the pthread library also brings according symbols, except they are suffixed with some #GLIBC... stuff. Didn't check linker/loader tricks so far.
A sample like
#include <stdio.h>
#include <unistd.h>
#include <pthread.h>
static void *fooo (void *xxx) {
char *txt = (char*)xxx;
printf("My job is to print this :'%s'. Bye now!\n", txt);
return 0;
}
int main (int argc, char *argv[]) {
pthread_t thd;
pthread_create(&thd, NULL, fooo, "A POSIX thread");
sleep(1);
return 0;
}
runs very well on the old system just saying
gcc -l pthread fooo.c && ./a.out
but breaks at the linking step with 4.8.2.
Any idea would be very welcome.
.M
Thanks to sfrehse, JoachimPileborg et al!
Indeed, success depends on argument order. I knew this fact for static linking, but it is new in processing of shared objects with gcc.
Does someone know what the background of this improvement is? It breaks innumerable build processes, and I guess thousands of tomatoes are being made ready against gcc.gnu.org .....
.M
For a week I've been struggling with compiling openCV programs. I've tried everything I could possibly find on the internet.
What I did is: I've downloaded OpenCV-2.3.1-win-superpack.exe and followed this official installation guide.
In the CMake (gui) my source was: D:\opencv and build destination was: C:\opencv.
I've also added C:\opencv\install\bin;C:\opencv\bin to my system's PATH variable.
What I want is to compile openCV programs on my Windows OS using MinGW's gcc/g++ compilers.
I've tried various gcc/g++ parameters that I've found on the internet and days playing with the -I and -L options the compiler can never find the openCV functions or structures.
What I am trying to compile:
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <cv.h>
#include <highgui.h>
int main(int argc, char *argv[])
{
// Nothing but create a window
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE);
cvMoveWindow("mainWin", 100, 100);
cvWaitKey(0);
return 0;
}
Error:
Input:
gcc test.c -o test -I"C:\opencv\install\include" -I"C:\opencv\install\include\opencv" -L"C:\opencv\install\bin"
Output:
...\ccK4MfHv.o:test.c:(.text+0xa0b): undefined reference to `cvFree_'
Or with g++:
Input:
g++ test.c -o test -I"C:\opencv\install\include" -I"C:\opencv\install\include\opencv" -L"C:\opencv\install\bin"
Output:
...\ccXCTKa1.o:test.c:(.text+0x1e): undefined reference to `cvNamedWindow'
Side note: trying to compile in VS2005 I get the same error.
Thank you for your time!
In case someone else needs to solve this issue, here's how I got the posted OpenCV/HighGUI sample code to compile in Windows 7 x64 using MinGW, MSYS, and CMake:
build OpenCV from source using MinGW/MSYS/CMake. This is because I could not get the MinGW compiled version in the OpenCV-win-SuperPack to link properly in MinGW/MSYS/Windows 7 x64.
For full reference, here's how I compiled OpenCV:
make sure you have an up-to-date CMake (v2.6 or later) and MinGW (with GCC, G++, and MSYS options) installed
if you want the new Qt-based OpenCV HighGUI front-end, you will need to install Qt 4 (SDK).
download a OpenCV source/superpack version 2.2 or later (I used OpenCV-2.3.1-win-superpack.exe)
unzip the contents to [OPENCV_SOURCE_DIR] (I put it in C:/opencv, so there should be a file at C:/opencv/README for example)
create a [OPENCV_BUILD_DIR] directory elsewhere (I used C:/opencv/build/mingw)
use the CMake-GUI tool, specify the source directory as [OPENCV_SOURCE_DIR], the build directory as [OPENCV_BUILD_DIR], and click "Configure".
you may wish/need to go tweak the options (e.g. I ticked "Qt" and "Qt-OpenGL" entries, then clicked "Configure" again, then had to provide the path to the qmake executable)
once you have finished configuring OpenCV, click "Generate"
in a MSYS terminal, browse to [OPENCV_BUILD_DIR], and run "make" to build the code (this may take a while)
once the has been built properly, run "make install", which collects the built code/libraries/include dirs into [OPENCV_BUILD_DIR]/install folder (or a different folder if you changed the corresponding option when using the CMake-GUI tool)
add [OPENCV_BUILD_DIR]/install/bin folder to the PATH environmental variable. If you do not know how to do this, then I'd recommend using the Path Editor GUI tool.
if you end up using Qt, you will also need to put the bin folder of Qt SDK in the PATH environmental variable. This is the folder that includes qmake.exe.
put the following sample code into a file called test.c. I modified the includes slightly to make them compatible with OpenCV v2.2 and above.
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <opencv/cv.h>
#include <opencv/highgui.h>
int main(int argc, char *argv[])
{
// Nothing but create a window
cvNamedWindow("mainWin", CV_WINDOW_AUTOSIZE);
cvMoveWindow("mainWin", 100, 100);
cvWaitKey(0);
return 0;
}
in a MSYS terminal, browse to the folder where you put test.c, and run:
gcc -o test -I"[OPENCV_BUILD_DIR]/install/include" test.c \
-L"[OPENCV_BUILD_DIR]/install/lib" \
-lopencv_core[OPENCV_VERSION] \
-lopencv_imgproc[OPENCV_VERSION] \
-lopencv_highgui[OPENCV_VERSION]
So in my case:
gcc -o test -I"/c/opencv/build/mingw/install/include" test.c \
-L"/c/opencv/build/mingw/install/lib" \
-lopencv_core231
-lopencv_imgproc231
-lopencv_highgui231
Path Editor: http://www.redfernplace.com/software-projects/patheditor/
You have the directory, C:\opencv\install\bin, to locate libraries on the gcc/g++ command line, but I think you'll also need to specify the libraries to use as linker inputs as well. I'm not sure what libraries are part of the OpenCV distribution, but going by the example on the instruction page you linked to, one might be:
-lopencv_calib3d220.dll
You'll probably have to add one or more other ones (that follow the name pattern lib*.a in the C:\opencv\install\bin directory - or maybe some other lib directory that you should be passing in a -L option).
I wrote a c++ program using boost library in Xcode. Here is my code. It is very simple.
#include <iostream>
#include </usr/local/include/boost/math/special_functions/beta.hpp>
using namespace std;
using namespace boost::math;
int main (int argc, char * const argv[])
{
double a = 100.0;
double b = 100000.0;
double x = 0.3;
double result = beta(a, b, x);
cout << result << endl;
return 0;
}
But when I tried to build it in the Xcode, there popped up a lot of errors related to the library linking stuff. I noticed that the compiler that Xcode was using was "System Default: gcc 4.2". And all other options are gcc or LLVM gcc (I have no idea what this is).
I later tried to compile the file simply using terminal. Weird thing happened. If I compile it with g++, without any extra flags, the compilation completed successfully and the the program could be ran normally; but if I compile it with gcc, there are pages of errors.
So, to sum it up, while using g++, everything is OK; while using gcc, everything is not OK. Since the Xcode is using gcc, the program could not be compiled using Xcode.
(And I kind of need to use the Xcode because this is just a test program, I actually have a much bigger project to handle and I depend on the debugger of Xcode.)
So my question is, WHAT THE HELL is the difference between gcc and g++? Or how can I change the compiler of Xcode to g++?
gcc is a C compiler.
g++ is a C++ compiler.
You're trying to compile C++, ergo, you need to use a c++ compiler.
Googling "Using XCode for c++" brings up lots of results, but this one seemed fairly straightforward and had pictures:
https://www.cs.drexel.edu/~mcs171/Wi07/extras/xCode_Instructions/index.html
The gcc command compiles C files (although you can use -libstdc++) to link C++ files as well but I don't recommend it.
The g++ command works for C++ files which is why it worked in your case.
For XCode you have to change the compiler from GCC to G++ for it to successfully work.
I am currently running a MacBook Pro with Mac OS X Version 10.5.8. I downloaded XCode version 2.5 and installed it.
Further, I added /XCode2.5/usr/bin to my PATH.
Here is hello.cc program:
#include <iostream>
int main(void)
{
std::cout << "hello, world" << std:endl;
}
Here is what happens:
$> g++ hello.cc
hello.cc: In function ‘int main()’:
hello.cc:5: error: ‘cout’ is not a member of ‘std’
hello.cc:5: error: ‘endl’ is not a member of ‘std’
Is setting the PATH not sufficient to run the gcc utilities from the command line on a Mac?
Thanks,
Charlie
There is a typo in the code as you've represented it here:
std::cout << "hello, world" << std:endl;
^
|
std::endl
However, once I fixed that it seemed to compile and run fine (g++ 4.2.1 installed with XCode on OS X 10.6.2)
This works:
#include <iostream>
using namespace std;
int main()
{
cout << "hello, world" << endl;
return 0;
}
It has been awhile -- as I remember the installation from the Mac OS install DVD (10.4?, 10.5?), two versions of gcc were provided, one for use with XCode, the other for use from the command line. The version for use from the command line installs to /usr/bin. I don't have /XCode2.5/usr/bin on my PATH, and am able to use gcc, etc. I think that you probably want a different download. The version of gcc that is installed to /usr/bin will install libraries in locations that are automatically searched. No modification to PATH or other settings is necessary.
Alternatively, it is easy to install more recent versions of gcc using MacPorts. These are installed in /opt/local/bin, and the PATH must be modified. The MacPorts versions use modified names so that they won't conflict with the standard Apple-supplied version.
Well after some searching, I found a link to http://connect.apple.com as opposed to (developer.apple.com).
The former site still had a link to XCode 3.1.4 under "Download > Development Tools"
Once I downloaded and installed that (and changed my PATH back to the default), then g++ and gcc work fine.
Thanks all for the quick advice.