Adding sources for shared library in GDB - debugging

How to add source code of some_shared_library.so into gdb.
I've tried to use dir command but it has not helped.

In order for GDB to know what sources match your some_shared_library.so, you must build it with debugging info (usually -g flag).
Once you've done that (and it sounds like you haven't), on many platforms (e.g. Linux) GDB will find the sources automatically. On other platforms, dir is the right command to tell GDB where the sources are.

Related

Dune debugging - OCaml

I know of the OCaml debugging tool (first compile with ocamlc -g <file>, then run ocamldebug <output>) and also the function call tracing feature in the toplevel (both covered here). However, I can't seem to find anything about debug builds with dune. Is this possible? Can someone point me in the right direction? Thank you!
The -g flag is present by default in all build profiles, so the short answer is that you don't need to do anything. As a pro tip, if you want to see what flags are set by default use
dune printenv .
or for the given building profile, e.g., for release,
dune printenv --profile release .
In a general case, flags are added using flags, ocamlc_flags, and ocamlopt_flags fields that are accepted by env, library, executable, and executables stanzas and have the corresponding scopes. If you want your flag to be applied globally you need to add the corresponding flag field to env stanza, e.g.,
(env
(release
(ocamlopt_flags (:standard -O3))))
Here :standard expands to the standard set of flags.
It is also worth to know that OCaml native executables (the executables compiled to machine code using ocamlopt) do not work with ocamldebug. You can use either gdb, which OCaml supports pretty well or use bytecode executables.

How to run a C program in android-x86 terminal?

I have to C program which is compiled using gcc in ubuntu. I want to run that executable in android terminal. When i run it is showing either "file or directory is not found" or "not executable:ELF32".
I want to run the code in android terminal. Is there any way or flags in gcc or using any other compiler so that i can run my code in the android terminal.?
Android does not use the same system libraries as Ubuntu, so they will not be found.
There are two solutions:
Copy the libraries you need.
If you can place them in the same filesystem locations they have in Ubuntu then great, otherwise you'll need to run the ld-linux.so manually and tell it where to find the libraries. Or, you could relink the program such that it expects to find the dynamic linker and libraries in a non-standard place. You might also use a chroot, but that requires root, and you'd need to find a chroot binary that works.
Use a static link.
This usually just means passing -static to GCC. You get a much larger binary that should be entirely self-contained, with no dependencies. It requires that static versions of all your libraries are available on your build system. Also, some features (such as DNS lookup) always expect a shared library, so they won't work this way.
Even then, you should expect some Linux features to not work. Basically, anything that requires hardware features or configuration files in /etc are going to need a lot of effort. There are various projects that have done this already (search "linux chroot android").
I'm not sure what the "not executable:ELF32" message means, but you should check whether you're building 32 or 64-bit executables, and which the Android binaries are using (file <whatever> should tell you).

How do I create an executable file with OpenCOBOL?

Upon finishing a COBOL program, how do I compile it into an executable file that may be run on other PCs? I'm using OpenCOBOL via cygwin.
Check out this getting started page from the user manual for OpenCOBOL:
But in case the link is broken, just do this:
$ cobc -x hello.cob
$ ./hello
cobc is the compiler. hello.cob is the source file. The output is simply the file hello which can be run by calling ./hello. The -x option is necessary to build an executable.
However, with all compiled programs, it is compiled for the machine is was built on. It will work on machine with similar architectures, but you don't true cross-platform ability unless you're using an interpreted language like Python or Java.
If you compile with Cygwin, the target computers also need Cygwin, or in particular the cygwin dynamic libraries along with the OpenCOBOL runtimes.
Many times, you can also compile under MinGW, which lessens the dependencies, but also lessens the available POSIX features.
Easiest path, install OpenCOBOL and Cygwin on the target machines, and you'll be good to go, otherwise you'll need to produce release packages with all the dependencies and instructions for PATH settings.

USB GCC Development Environment with Libraries

I'm trying to get something of an environment on a usb stick to develop C++ code in. I plan to use other computers, most of the time linux, to work on this from a command line using g++ and make.
The problem is I need to use some libraries, like Lua and OpenGL, which the computers don't have. I cannot add them to the normal directories, I do not have root on these computers. Most of the solutions I've found involve putting things in /usr/lib/ and the like, but I cannot do that. I've also attempted adding options like '-L/media//lib', which is where they are kept, and it didn't work. When compiling, I get the same errors I got when first switching to an OS with the libraries not installed.
Is there somewhere on the computer outside of /usr/ I can put them, or a way to make gcc 'see' them?
You need more than the libraries to be able to compile code utilizing those libraries. (I'm assuming Linux here, things might be slightly different on e.g. OSX,BSDs,Cygwin,Mingw..)
Libraries
For development you need these 3 things when your code uses a library:
The library header files, .h files
The library development files, libXXX.so or libXXX.a typically
The library runtime files , libXXX.so.Y where Y is a version number. These are not needed if you statically link in the library.
You seem to be missing the header files (?) Add them to your usb stick, say under /media/include
Development
Use (e.g.) the compiler flag -I/media/include when compiling source code to refer to a non-standard location of header files.
Use the compiler/linker flag -L/media/lib to refer to non-standard location of libraries.
You might be missing the first step.
Running
For dynamically linked libraries, the system will load those only from default locations, typically /lib/ , /usr/lib/
Learn the ldd tool to help debug this step.
You need to tell the system where to load additional libraries when you're running a program, here's 3 alternatives:
Systemwide: Edit /etc/ld.so.conf and add /media/libs there. Run ldconfig -a afterwards.
Local, to the current shell only. set the LD_LIBRARY_PATH environment variable to refer to /media/lib, run export LD_LIBRARY_PATH=/media/lib
Executable: Hardcode the non-standard library path in the executable. You add this to the linking step when creating your executable: -Wl,-rpath,/media/lib
Etc.
There could be other reasons things are not working out, if so,
show us the output of ls -l /media/libs , and where you put the library header files, the command line you use to compile/link, and the exact errors you get.
Missing the headers and/or development libraries (for dynamic libraries there is usually a symlink from a libXXX.so to a libXXX.so.Y , the linker needs the libXXX.so , it will not look directly at libXXX.so.Y)
using libraries not compatible with your current OS/architecture. (libraries compiled on one linux distro is often not compatible with another distro, or even another minor version of the same distro)
using an usb stick with a FAT32 filesystem, you'll get in trouble with symlinks..

Trying to compile and debug C++ from Vim

I've been learning C++ and Allegro using Code::Blocks on Windows XP, and recently felt like learning Vim. However, I have no idea how to compile a program "manually" (i.e., without using an IDE).
For compiling from within Vim, I have gotten as far as setting the makeprg to gcc, but I understand I also need a makefile. What is that and how do I write one? Is it with the makefile that I can use libraries such as Allegro?
Also, I've gotten quite fond of the CB debugger (I'm using gdb). Is it possible to do something similar with Vim?
Thank you.
Look at MinGW. I would avoid Cygwin if you only need gcc and make. You'll want both MinGW and MSYS. MSYS has a windows port of make.
If you're interested in more unix utlities for the windows command line I recommend CoreUtils.
For learning make see the manual
You don't necessarily need a Makefile, but it's the preferred (and possibly sanest) way of compiling code on UNIX-like systems.
I don't know if GNU Make has a Windows port, but you can probably run it under Cygwin.
To learn more about GNU Make and Makefiles:
make (Wikipedia)
GNU Make
GNU Make Manual
Also, see this question: compile directly from vim
Mandatory edit: I don't use Windows or Cygwin. You might want to take epochwolf's advice on that department.
I'm not in expert in makefiles and debugging but I know that Vim lets you do many things.
For example if you want to compile a file with gcc, it's not very different from the usual way. In normal mode type:
:!gcc file.c -o file
In fact you can use (almost) every system command just by adding "!" in front of your command.
gdb also works with Vim
:!gdb
I hope it will help you.
To integrate vim with devenv, you can use devenv from Visual Studio to complie the project in vim. The command as follows:
Devenv SolutionName /build SolnConfigName [/project ProjName [/projectconfig ProjConfigName]]
Typicatlly, the devenv should located in C:\Program Files\Microsoft Visual Studio 8\Common7\IDE. Set it to the path of environment to make it callable from vim. We also need to make vim recognize the error messages thrown by the commandline build tool devenv. Just put the following lines in your vimrc:
" Quickfix mode: command line devenv error format
au FileType cpp set makeprg=devenv.com\ /Build\ Debug\ *[SolutionName]*
au FileType cpp set errorformat=\ %#%f(%l)\ :\ %#%t%[A-z]%#\ %m
Then You can use :make to compile and build the program from vim.
EDIT1: A few bookmarks you might find useful:
GNU make tutorial (this one uses gcc and make, so it should be right up your alley)
Another one
Win port of some of GNU utils Can was mentioning; I personally use these and haven't had any problems with them on Windows platform.
Yes, you can compile without the makefile. If your program is simple (for example, one file only) you can compile by calling the compiler and including the name of the program in the same line (don't remember how it goes with gcc). Of course, to make things easier this can be mapped to a key within vim, so you don't have to jump to command prompt and back.
If you are working on a bigger project, which consists of several files and such, than a makefile is useful. It will "search" through the files, determine dependencies, include them in the build, maybe put the source files in one directory and the resulting exe file in the other and such. So it is more of a linking and building system than just compiling.
Although the GNU make mentioned in Can Berk Guder's answer is a popular one, there are quite a number of other tooks for "building makefiles" ("makefile" has become a type of synonym for that kind of operation) - here, you can see some other options on this link. Due to its part in history vim has good support for :make, but others can be easily used as well (there are a lot of texts on this subject on VimWikia.
Well, that's it. Just my 0,2 euros :)
As long as you have GNU-make installed (with cygwin or mingw under windows), you don't need to write a makefile for single-file projects. Just run :make from vim, and that's enough.
If your project is made of several files, then you will have to write a makefile (or any equivalent for scons, aap, (b)jam, ant, ...), tune your &makeprg in consequence, and finally call :make from vim. See the relevant category in vimtips. You can of course run the compiler as you would have ran any other external tool, but you would loose the possibility to jump to the line(s) of the error(s).
NB: if you are using the win32 version of vim, and gcc-cygwin, you'll need to translate the error messages obtained. I used to maintain a perl script for this purpose, it is now part of a bigger suite (still in beta stage)
Regarding your question about debugging, it can't be done from vim under windows for the moment. The only debugger that can be integrated so far is gdb, but under linux only ; see the pyclewn (.sf.net) project.
I'm not sure about debugging, but I know an easy way to compile and run the current program as I wrote a small vim plugin to do so.
http://pastebin.com/qc5Zp2P7
It assumes you are using the g++ compiler. If not, just change the name to the compiler you're using. Save this file to whereveryouinstalledvim/ftplugin/cpp.vim
In order to compile and run the currently open program, just type shift-e while in non-editing mode.

Resources