I am using scientific linux. I am dealing with a huge amount of code in C++ with tons of cpp files. Right now, it compiles successfully, but the values/data I'm getting are definitely wrong. Also, for some small changes I make to the code causes seg faults.
In the directory user/project/Build, I enter make to compile and link all the cpp files. I then have to go to user/project/Build/bin/project to run the project binary by typing user/run/run.sh
When I go to directory /user/project/Build/bin and then type gdb project and then run, I see
Program exited with code 01. Missing separate debuginfos, use: debuginfo-install glibc..
If I try to set a breakpoint, such as by break test.cpp:19, I get the message No source file named test.cpp.
Make breakpoint pending on future shared library load?
But I clearly have a source file named test.cpp
How can I set breakpoints? Considering that I'm a beginner with Unix, should I use another IDE such as emacs or Qt creator?
Did you read the documentation of GDB? It is definitely worthwhile to read it. Read also some tutorial on gdb
If your Makefile-s are generated by cmake, you should also study the documentation of cmake and the documentation of make. See also this answer to a related question.
Did you compile all your software with g++ -Wall -g (and without any optimization flags like -O1 or -O2) - or perhaps even -g3 instead of -g?
You might even install debugging variants of the major libraries you are using (e.g. packages like glibc-debuginfo etc...)
You probably want to specify (for gdb) the source directories to search with the dir command of gdb ...
And yes, I recommend using emacs. But above all, I strongly recommend spending hours (and perhaps days or even weeks) to learn more about Linux and software development on it (there are lots of books, websites, tutorials and other training, ... about that). Maybe start with a small, hello-world like, program (learning how to compile it with g++ and to debug it with gdb). Then try to compile and debug a small (e.g. of a hundred thousand lines of source code) free software that you like (e.g. fishshell or anything you've got from sourceforge or github), just to get a feeling of how such software is built.
If you are using (or improving) a big scientific software, it probably has some community website, mailing list, or forum for help (see geant or kiva or aster as examples, which I only know by name!). Please also use them.
PS. It is not mostly a matter of choosing tools: you are using the good ones (GCC i.e. g++, emacs, gdb, make, grep or ack, etags, git, awk, ....). It is a matter to get the knowledge -spending weeks or months of your time- about how to use them wisely and combine their use. See also this & that.
Related
I have a larger C++ programm with lot of templates which i want to debug. Unfortunately gdb takes several minutes to read the symbols.
http://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html contains lots of options for debugging.
Which options would you suggest to make gdb faster/more usable.
Update: It looks like the slow down is caused by libtool. If gdb is launched via libtool --mode execute it is slow. If gdb is launched gdb .libs/foo it is reasonable fast. Any ideas why is much slower?
Update: Another suggestion was -fvisibility=hidden see http://gcc.gnu.org/wiki/Visibility
Sometimes using -fdebug-types-section can make things a bit faster. It isn't guaranteed though.
Several minutes to load ... I wonder how big this executable is. If I were desperate I might try only compiling selected modules with debug info. Or perhaps look to see if it is a gdb bug. If it is split into an executable and some shared libraries, and some parts don't change very often, you could also look into using the "gdb index" feature (see the manual) to speed up the loading of debuginfo for those modules.
I'm currently running a variant of Eclipse known as WindRiver, which is designed for embedded systems programming using C++ (specifically, I'm part of my high school's FIRST Robotics team).
I'm able to successfully compile and build the project from within Eclipse (Project > Build Project) but I'm looking for ways to automate this process by compiling by using the command line.
The project already contains a makefile and everything, so ideally I want to be able to just run that without making any manual changes. I pastebin'd the makefile in case its relevant.
Does anybody know where I can find more information on compiling C++ programs from the command line for either Eclipse or WindRiver or on running makefiles on Windows? I tried looking at "How to run a makefile in Windows?" but following the first answer didn't work (it gave a syntax error for the makefile).
I'm currently using a Windows 8 laptop. As best as I can tell, the current varient of WindRiver I'm using is based on Eclipse version 3.3.1.
You will need a make utility, I believe your WindRiver / Eclipse setup would come with "gnumake" (probably called either make or gmake). You'd nee dto set up the command line path to lead to the compiler and the make executable. Unfortunately, this is not a great answer, as I can't give you exact links to the make and compiler locations (it would of course also depend on where you installed things). I just thought I'd lead you somewhat on the right path, since the question has been up for a little while and no one jumped at it.
Thanks to Mat Petersson's answer, I was able to identify everything I needed and create a batch file that could compile the file for me:
#echo off
setlocal
set PATH=%PATH%;C:\WindRiver\gnu\3.4.4-vxworks-6.3\x86-win32\bin;C:\WindRiver\utilities-1.0\x86-win32\bin;C:\WindRiver\setup\x86-win32\bin
set WIND_BASE=C:\WindRiver\vxworks-6.3
cd My_Project\PPC603gnu
make --no-print-directory BUILD_SPEC=PPC603gnu DEBUG_MODE=1 TRACE=1
I'm usually using Visual Studio, but several things bother me when I just quickly want to test some code:
it has a rather long startup time
it always needs a project to execute/debug files
program output gets printed to the console, but the window simply closes when I don't insert a getchar() or a breakpoint in the program and thus I'm not seeing it.
I'm looking for a program which is suitable for a really, really quick programming in Windows. Such as, copying some code from an SO question, running it and seeing its output.
I don't think that console programs or g++ under CygWin are a good solution, because there it takes ages to cd into the right dir to save the file, I'm not used to editors such as Vim, and typing in the compiler commandline myself has always annoyed me etc.
So I guess what I'm looking for is a very lightweight free C/C++ IDE which is preconfigured to work with a free compiler (bonus points if it is even shipped with it.)
What can you recommend which adresses at least two items from the list above?
Is there maybe even a program which can execute/interpret C or C++ in an interactive commandline (like Python)?
I'm looking for a program which is suitable for a really, really quick
programming in Windows. Such as, copying some code from an SO question
and executing it and seeing it's output.
For quick-and-dirty experimental coding, I really like codepad.org. Not having to create a file is especially nice as it saves me from coming up with a suitable name and disk location. Be aware that it uses g++ 4.1.2 behind the scenes so some of the latest C++11 features aren't supported.
"really, really quick (and dirty, throw away?) programming "?
Compiler : VC++ command line - you already have it.
Editor: Notepad or somesuch
Compilation process: A .BAT file you write once
and supply a parameter with the name of the single source file.
Location: Set up some desktop shortcuts to a known directory for your
test code.
Use TCC : Tiny C Compiler
start a command prompt
cd wherever
notepad main.c
write code in notepad. save
back in the command prompt type tcc -run main.c
notice errors, go back to 4
Note that with -run parameter you're invoking tcc like an interpreter
Which compiler you use doesn’t really matter. I prefer G++ but cl.exe (from Visual Studio) works equally well.
In order to use the compiler quickly from the command line, either
include it into your PATH variable by setting it in the system settings, or
create a simple .cmd script which launches a console with the right paths included.
Visual Studio incidentally comes bundled with such a .cmd script which is linked in the Start Menu entry of Visual Studio. Personally, though, I prefer adjusting the PATH variable.
Then you can simply invoke the compiler from any directory in the command line. If you are too lazy to write the whole command line, create a script to do it for you. Or use Cygwin and (C)Make.
Two additional remarks:
Starting the project using the build configuration (Cntr+F5 (?)) leaves the console open after the program has run, without you having to include getch() calls or similar.
I highly recommend you learn an editor such as Emacs or Vim, unless you plan never to use any other platform than Windows, and even then. These editors are just tremendously powerful, and in some ways light-years beyond what the Visual Studio code editor offers.
But if you really don’t have the time, use a decent text editor such as Notepad++ instead.
Open Watcom is easy to install and use, it's fast and it's the closest compiler to MSVC++, although it's noticeably behind in features (especially in C++).
I don't use its IDE at all as I got used to doing most of the stuff in the console, but it's there and the debugger is there too.
Compiling one-filers is easy.
Compiling C code:
wcl386.exe /we /wx /q sourcefile.c
Compiling C++ code:
wcl386.exe /xs /we /wx /q sourcefile.cpp
On my machine, I have a "empty" project called "Test". When I want to test some random code on the internet, I simply put it into main.cpp in that project, and compile.
If you think MSVC takes too long to load, it should be possible to write a batch script that attempts to compile the project and puts the build log in a file. Then you can simply alter the existing main.cpp with notepad, double click the batch file, then pop open the build log or run the executable.
[Edit] I made a batch file to compile the entire solution. Turns out that requires loading visual studio. However, the batch file can compile/run a single cpp file easy enough.
My favorite IDE: http://www.codeblocks.org/
Here is a direct link to the download that includes the MinGW compiler: http://download2.berlios.de/codeblocks/codeblocks-10.05mingw-setup.exe
You're not gonna find any (good) C/C++ interpreters.
Once I used PSPad setting its "compiler" option for C++ files to a reasonable default (cl.exe in the correct directory, speed optimization, all warnings). Then it's just Ctrl+F9.
All of the above compiler recommendations are good. For an editor, I really like Notepad2
I know you didn't ask...
First off, your expectations are not reasonable. no program can guess what you want, over a range of input from the simplest to the most complex. If cd'ing into cygwin is too hard, and starting up visual studio is too time-consuming, you're pretty much toast. Sorry.
That said, you can edit code with notepad (which you can invoke from the command line as notepad foo.cpp). Notepad uses your mouse and the arrow keys on your pc so it's pretty intuitive.
you can use visual studio tools from the command line, without having to fiddle with project files.
Visual studio comes with a tool called nmake, the most basic usage of which is similar to linux make. If you have very simple input, nmake's default rules may be good enough to produce an executable. If not, you may be able to construct a makefile that will take any single simple file, say foo.cpp, and compile and link it to an executable called foo.exe. You'll still have to learn to use nmake, which some people think is easy, and others think is fiendishly difficult. Try nmake foo.cpp and see if the result is what you want.
I've developed a tool in C++, using Visual Studio 2010, which I'd like to deploy on Linux systems as well. The code itself is programmed entirely platform-independent, using only the STL and the standard library.
Now my problem is: I don't have experience with Linux.
I have, however, tried to get some other programs I wrote to compile using GCC, and the results were a truckload of errors being thrown at me, which took me 3 hours to resolve - the horrors!
Noting from this experience I think that the same is about to happen, just a lot worse, if I try to port my current project to GCC.
My questions are:
What does a Visual Studio user need to know to successfully get their program running on Linux?
(do I need to learn make?)
Do you know of a good source which covers not the topic of GCC / Linux programming as a whole, but specifically the problem of switching from a Visual Studio environment?
I recommend skipping make altogether, its a rather old technology and you may face portability issues while using it. Instead, learn another build system like CMake http://www.cmake.org/ or SCons http://www.scons.org/
I use CMake myself and find it to be excellent. You write very simple build scripts (you can easily get started in an hour or two) and it generates the makefiles for you. The biggest advantage is that it can generate makefiles for almost any compiler or build system you could want. It can generate standard unix makefiles, Microsoft Visual C++ Projects, XCode Projects, Code::Blocks projects, even KDevelop and Eclipse CDT4 projects.
I haven't used SCons myself, but I do know that it actually builds your program for you and runs on python.
Getting started in Linux/Unix can really mean anything you want. Going from Visual Studio can mean going to Eclipse or another IDE, which is as simple as learning the new IDE, or it can mean going straight to the shell and forgetting you ever knew what an IDE looked like. My personal recommendation is to stick with the IDE- Eclipse is great as an industry standard and its very cross-platform (just get the CDT plugin).
On the topic of the GCC, you probably won't really be invoking it yourself very much if you're writing CMake scripts since CMake will generate the makefiles. The simplest command line arguments are:
g++ <source-files> -o <output-name> -I <another include directory> -l <library to link to>
as an example:
g++ helloworld.cpp -o world.out -I /usr/include -l mylib
To run an executable from the shell, navigate to the directory its in and type:
./world.out
Note that the default output when invoking g++ (i.e. g++ helloworld.cpp) is a.out.
And that's all you really need to know! The rest comes easily. You'll learn to love Unix, and I really recommend learning the shell even if you do go the path of the IDE. It can make your life alot easier.
EDIT: So to port your program to Linux and the GCC with CMake, here's what you would do:
Get CMake
Write the CMakeLists.txt file in your source directory (its the Makefile format CMake uses)
Invoke CMake on the directory. CMake will parse the CMakeLists.txt file automatically and generate build scripts of your choice
Build with whatever build system you used. If you're using standard Unix Makefiles, it'll mean just navigating to the build directory and typing make into the shell
Your project will be built and youre done!
P.S: I never learned normal make, although it definitely has its uses. CMake found an eager user in me.
i was going to say "man g++" but that manual is very long in lines.
just type
g++ main.cpp utility.cpp
g++ will automatically compile and link main.cpp, utility.cpp into a file named a.out
type ./a.out into command line to run the compiled code.
you won't need to learn make, but if you do, simple make scripts only take 4-5 lines of code. It's pretty easy to type in, but it's actually pretty different for a visual studio user, so it's completely non-friendly if you put bad code your Makefile.
about learning linux, there's a lot to learn. I can't even tell you where to start, but there's no secrets. Not like Microsoft products where you have to learn the workaround to make your code run.
oh and here's g++ info: http://homepages.gac.edu/~mc38/2001J/documentation/g++.html
I decided to leave my windows install behind and am now running Debian as my default OS. I have always coded in Windows and specifically with Visual Studio. I am currently trying to get used to compiling my code under linux.
Although I still have a lot of documentation to read, and don't expect you guys to make it too easy for me, it'd still be nice to get some pointers on where to start. I have some specific questions, but feel free to suggest/recommend anything else regarding the subject.
What are recommended guides on creating a make file, how do I compile from this makefile (do I call g++ myself, do I use 'make'?)
Looking at other linux software, they almost always seem to have a 'configure' file. What exactly does it do? Does it only check if the required libraries are installed or does it more than just checking requirements?
How do I link libraries, and how does this relate to my makefile or g++ parameters? In windows I would compile the library, include some header files, tell my linker what additional lib file to link, and copy a dll file. How exactly does this process work in linux?
Recommendations for code editors? I am currently using nano and I've heard of vim and emacs, but don't know what the benefits of them are over eachother. Are there any others, and why would I consider them over any of the previous three? Note: I am not looking for an IDE.
Any help, links to guides & documentation (preferably those that are aimed at beginners) are very much appreciated!
What are recommended guides on creating a make file, how do I compile from this makefile (do I call g++ myself, do I use 'make'?)
You build from the makefile by invoking "make". And inside your makefile, you compile and link using g++ and ld.
Looking at other linux software, they almost always seem to have a 'configure' file. What exactly does it do? Does it only check if the required libraries are installed or does it more than just checking requirements?
It's a script usually used to set up various things based on the environment being used for building. Sometimes it's just a basic shell script, other times it invokes tools like Autoconf to discover what is available when building. The "configure" script is usually also a place for the user to specify various optional things to be built or excluded, like support for experimental features.
How do I link libraries, and how does this relate to my makefile or g++ parameters? In windows I would compile the library, include some header files, tell my linker what additional lib file to link, and copy a dll file. How exactly does this process work in linux?
ld is the GNU linker. You can invoke it separately (which is what most makefiles will end up doing), or you can have g++ delegate to it. The options you pass to g++ and ld determine where to look for included headers, libraries to link, and how to output the result.
Recommendations for code editors? I am currently using nano and I've heard of vim and emacs, but don't know what the benefits of them are over eachother. Are there any others, and why would I consider them over any of the previous three? Note: I am not looking for an IDE.
Vim and Emacs are very flexible editors that support a whole bunch of different usages. Use whatever feels best to you, though I'd suggest you might want a few minimal things like syntax highlighting.
Just a note to go with MandyK's answers.
Creating make files by hand is usually a very unportable way of building across linux distro's/unix variants. There are many build systems for auto generating make files, building without make files. GNU Autotools, Cmake, Scons, jam, etc.
Also to go more in depth about configure.
Checks available compilers, libraries, system architecture.
Makes sure your system matches the appropriate compatible package list.
Lets you specify command line arguments to specialize your build, install path, option packages etc.
Configure then generates an appropriate Makefile specific to your system.
What are recommended guides on
creating a make file, how do I compile
from this makefile (do I call g++
myself, do I use 'make'?)
I learned how to write makefiles by reading the GNU Make manual.
Looking at other linux software, they
almost always seem to have a
'configure' file. What exactly does it
do? Does it only check if the required
libraries are installed or does it
more than just checking requirements?
The configure file is usually associated with autotools. As the name of the script suggests, it allows you to configure the software. From the perspective of the developer this mostly means setting macros, which determine variables, which libraries are available, and such. It also tests for the availability of libraries. In the end the script generates a GNU Makefile, which you can then use to actually build and install the software.
The GNU build system is only one of many. I don't particularly like the GNU build system as it tends to be slower than others, and generates an ugly Makefile. Some of the more popular ones are CMake, Jam (Boost Jam might be of interest for C++) and waf. Some build systems simply generate Makefiles, while others provide a completely new build system. For simple projects writing a Makefile by hand would be easy, but "dependency checking" (for libraries, etc) would also have to be done manually.
Edit: Brian Gianforcaro also pointed this out.
Your question is a bit too general, but here is what I would recomment:
Editor: vim and emacs are popular. What matters the most, as with most tools, is to master one. I like using vim because vi (its descendant) is available everywhere, but that may not be very relevant, specially if you stay on Linux. Any programming editor is fine.
configure: unless you do big projects, don't bother with it. It is a nightmare to use and debug. It only makes sense if you intend to distribute your project - in that case, read the autobook: http://sources.redhat.com/autobook/. As other said, there are alternatives (cmake, scons, etc...). I am quite familiar with both scons and autotools, but I still use make for small (couple of files) projects.
Concerning shared library: it is almost as windows, except that you link against the shared library directly - there is no .lib vs .dll distinction in Linux. For example. for one library foo with a function foo:
int foo(void)
{
return 1;
}
You would build it as follows:
gcc -fPIC -c foo.c -o foo.o
gcc -shared foo.o -o libfoo.so
A main (of course in real life you put the API in a header file):
int foo(void);
int main(void)
{
foo();
return 0;
}
And then, you link it as:
gcc -c main.c -o main.o
gcc main.o -o main -L. -lfoo
The -L. is here to say that you want the linker to look in the current directory (contrary to windows, this is never done by default in Linux), the -lfoo says to link against the library foo.
So to get you started I will first point you to this guide for makefiles, it also covers some linking stuff too.
It's just a little something my university Computer Science prof gave us I found it to be very clear and concise, very helpful.
And as for an IDE, I use eclipse usually because it handles the makefile as well. Not to mention compile and standard output are right at your fingertips in the program.
It was mainly intended for Java developing, but there is a C/C++ plugin too!
Recommendations for code editors? I am
currently using nano and I've heard of
vim and emacs, but don't know what the
benefits of them are over eachother.
Are there any others, and why would I
consider them over any of the previous
three? Note: I am not looking for an
IDE.
Vi and Emacs are the two quintessential Unix editors; if you are set on using a text editor rather than an IDE, one of them or their derivatives (vim, xemacs, etc) is the way to go. Both support syntax highlighting and all sorts of features, either by default or via extensions. The best part about these editors is the extensibility they offer; emacs via a variety of lisp, and vim via its own scripting language.
I personally use Emacs, so I can't say much about Vim, but you should be able to find lots of information about both online. Emacs has several good tutorials and references, including this one.
EDIT [Dec 2014]: There seems to be a trend of cross-platform and highly extendable editors recently. This could be a good choice if you'd like something less than an IDE, but more graphical than vi/emacs and native-feeling across multiple platforms. I recommend looking at Sublime or Atom; both of these work across Windows/Linux/Mac and have great communities of plugins and themes.
I recommend the book The Art of Unix Programming by ESR. It covers choice of editor, programming language, etc. It also gives a good sense for the mindset behind programming on Unix or Linux.
For editors, you probably want either Vim or Emacs. They are both different and which one is better is more about personal taste than anything else. I use Vim. It is great for quickly moving around the code and making changes. I didn't like Emacs as much but many people do. Emacs is extremely extensible and can be used for everything from a news reader to an ide. Try both and see what you like.
Recommendations for code editors? I am currently using nano and I've heard of vim and emacs, but don't know what the benefits of them are over eachother. Are there any others, and why would I consider them over any of the previous three? Note: I am not looking for an IDE.
If you're using Linux with a window manager (KDE, Gnome, etc.) you could also consider using the standard text editor for your window manager. The main benefit it would have over vim/emacs/nano is that it would seem more familiar to one coming from a Windows environment - an editor written to run on the window manager has a menu bar, file open/save dialogs, undo/redo, and plenty of other neat features that console editors probably can't match. (Though emacs and vim are pretty sophisticated these days, so who knows ;-P)
On KDE (which is what I use) I can recommend KWrite, which is a well-featured but fairly basic text editor with syntax highlighting; or Kate, which is a fancier text editor with some extra features: session management, a builtin terminal panel, automatic invocation of make, and several plugins including a C/C++ symbol viewer. I usually use Kate for my C++ work when I don't want to bother with setting up a full IDE project. (FYI the IDE for KDE is KDevelop)
the space between invoking g++ directly and using an autotools build chain is pretty narrow. Get good at autotools, which is really the closest thing to a 'project' available in the Linux/Open Source world.
For someone coming from Visual Studio, all this commandline stuff might seem arcane and messy.
Before you turn into a bash shell/vim/emacs junkie, try a few GUI based tools first so you have some transition time...
QT 4.5 with its QT Creator mini-IDE. This is the best framework, lightyears ahead of the competition.
Eclipse (C++) - From my experience with this on Windows, I find it's astounding ( This is probably the best Java application ever written )
KDevelop
Anjuta
If you use Delphi, Lazarus/FreePascal is a good alternative.
I'm sure the longhairs will scoff and claim that vim or emacs gives them the best and fastest development environment, but different strokes for different folks. Someone accustomed to an IDE will take some time to switch or may not wish to switch at all.
For all their editing prowess, creating GUI apps is certainly not a job for 80x25 tools.
It takes years to become an expert with the command line side of things, its more of a transformation of worldview than anything else.
As a side note amongst the proper answers here.. In case you wanna hit the ground running as a Windows guy, I'd suggest the fresh new Qt SDK. It will feel like home :-)
I advise using SCons in place of Make, it does the same job but it's easier to use and handle out of the box how to make dynamic libraries, dependencies, etc. Here it is a real life example for a simple prog
env = Environment()
env.Append(CCFLAGS='-Wall')
env.Append(CPPPATH = ['./include/'])
env.MergeFlags('-ljpeg')
env.ParseConfig("sdl-config --cflags --libs")
env.ParseConfig("curl-config --cflags --libs")
env.ParseConfig("pkg-config cairo --cflags --libs")
env.Program('rovio-pilot', Glob('./src/*.cpp'))
As a text editor, I'm happy with JEdit for coding, but it's a matter of taste.