I am writing a C language program on Linux and compiling it using GCC.
I also use a Make file.
I want to debug my program. I don't want to debug a single file, I want to debug the whole program.
How can I do it?
Compile your code with the -g flag, and then use the gdb debugger. Documentation for gdb is here, but in essence:
gcc -g -o prog myfile.c another.c
and then:
gdb prog
If you want a user-friendly GUI for gdb, take a look at DDD or Insight.
I guess that you are building from the command line.
You might want to consider an IDE (Integrated Development Environment), such as KDevelop or Eclipse, etc (hint - Eclipse ... ECLPISE ... E C L I PS E).
Use an IDE to edit your code, refactor your code, examine your code - class tree, click a variable, class or function to jump to declaration, etc, etc
And - of course - to debug:
run your code in the IDE
set breakpoints to stop at particular lines
or just step through, a line at a time
examine the call stack to see how you go there
examine the current values of variables, to understand your problem
change the values of those variables and run to see what happens
and more, more, more
p.s as wasatz mentioned- DDD is great - for visualizing the contents of arrays/matrices, and - imo - especially if you have linked lists
You can use gdb-based simple and useful GUI "Nemiver". It can debug your whole module comprising many source files.
Try cgdb
cgdb is a lightweight curses (terminal-based) interface to the GNU Debugger (GDB). In addition to the standard gdb console, cgdb provides a split screen view that displays the source code as it executes. The keyboard interface is modeled after vim, so vim users should feel at home using cgdb.
github repository
Related
I always use the -x (or debug flag) when it come to bash script, or shell scripts in general.
Now i'm curious to know, is there an equivalent, either using a specific compiler options, (i use gcc, but i don't mind any other compilers) or by using a specific code in my project?
Basically i just wanted a way to emulate what bash does (using the debug flag) which show which command/function was launched first, in order, and also show the output of said function, with additional errors message etc.But for C.
I'm aware of most debug option out there, especially considering the compiler, but i really wish i could do this in my C projects too.(especially the part where it show what is executed in order, like bash does with -x)
NB: There isn't any goal in this specific question beside the question itself, as i'm just curious if this exist, and thus don't have any need for it beside the actual knowledge acquired from said answered question.
Yes, you can mimic this behaviour with a debugger.
With GDB for instance you can write "Init Files" and "Command Files" in which you can write a simple loop:
break main
run
while 1
next
end
If you put a file named .gdbinit in the directory where you start gdb, this file will be executed or gdb will lead you on the way to configure it in order that it will be executed.
The other option is to pipe this file into your gdb-call:
gdb a.out < debug_me_like-x
Where the "debug_me_like-x" file is the one mentioned above.
As a reference for the "Command Files" have a look here.
Currently I am using Clion IDE plus latest version of Open Watcom v2 windows 32 bit compiler to develop some 16 bit MS-DOS application. The problem I have is I don't see all required debugging information when using watcom windows debugger (wdw.exe).
Being specific, I see global variables, global and any other types of functions, even those imported from asm files. But well, local variables list is empty all the time. But more importantly - the only c-code I can see is little test.c file which contains only main() function and nothing else except for includes.
What do I need to do to finally get c-level debugging for whole project? What am I missing?
I would be grateful for any help.
All source files is located in one directory, so, they all should be visible to debugger. But it sees only main c file.
Of course I am compiling with -d2 switch, as well as -hw. DEBUG WATCOM ALL is also presented in linker config file before any FILE directives. Reading manuals to compiler and linker... Well, it's nice that I've found many interesting things in manuals, but nothing helped with exactly that issue so far :)
List of compiler switches I currently using:
WCC.EXE:
CALL WCC.EXE -dTEST -bt=dos -0 -za99 -wx -we -mc -zp2 -hw -d2
%SRC_FULL_NAME%
WLINK:
CALL WLINK.EXE #..\CC.LK
CC.LK:
SYSTEM DOS
DEBUG WATCOM ALL
FILE TEST.OBJ
FILE LUTILS.OBJ
FILE LGL.OBJ
NAME TEST.EXE
OPTION ELIMINATE
...
I'm on a Mac and in terminal I'm compiling my program
gcc -Wall -g -o example example.c
it compiles (there are no errors), but when I try to provide command line arguments
example 5 hello how are you
terminal responds with "-bash: example: command not found"
how am supposed to provide the arguments I want to provide after compiling?
Run it like this with path:
./example 5 hello how are you
Unless the directory where the example binary is part of the PATH variable, what you have won't work even if the binary you are running is in the current directory.
It is not a compilation issue, but an issue with your shell. The current directory is not in your PATH (look with echo $PATH and use which to find out how the shell uses it for some particular program, e.g. which gcc).
I suggest testing your program with an explicit file path for the program like
./example 5 hello how are you
You could perhaps edit your ~/.bashrc to add . at the end of your PATH. There are pro and conses (in particular some possible security issues if your current directory happens to be sometimes a "malicious" one like perhaps /tmp might be : bad guys might put there a gcc which is a symlink to /bin/rm so you need to add . at the end of your PATH if you do).
Don't forget to learn how to use a debugger (like gdb). This skill is essential when coding in C (or in C++). Perhaps consider also upgrading your gcc (Apple don"t like much its current GPLv3 license so don't distribute the recent one; try just gcc -v and notice that the latest released GCC is today 4.8.1).
./example 5 Hello how are you is the syntax you're looking for.
This article lends a good explanation as to why this is important.
Basically, when you hit Enter, the shell checks to see if the first set of characters is an absolute path. If it's not, it checks the PATH variable to find executables with the name of the command you are trying to run. If it's found, it will be run, but otherwise it will crash and burn and you will become very sad.
I've never used a debugger and the time has come to give them a try. MinGW appears to come with GDB which I've been trying to use. Supposdly running gdb from the command line and typing run myprog.exe starts the debugger but when I do this I get
Starting program: C:\MinGW\bin\myprog.exe MyProg.exe
[New Thread 1828.0xd8c]
Error opening file.
[Inferior 1 (process 1828) exited with code 02]
How to proceed or what's an easier way?
In particular I'm trying to flush out undefined behavior.
Since your program terminates, you'll need to set a breakpoint to see anything. Try break main before the run line. Then you can do commands line next (next line), step (step into/outof function calls), print expression (where expression can be a variable name or a function-call or a calculation), display expression (same as print, but prints just before each prompt). At any given point you can type backtrace to get a call stack. You can even type up and down to move up the callstack, so you can print higher local variables.
Well, the easiest way would be to use an IDE, actually. You might want to give code::blocks a try - very easy to use, configures everything for you on installation (just make sure to pick a compiler - don't worry, it'll prompt you) and there, you're all set and ready to go. As it's multi-platform, it doesn't really lock you into windows either, and gives you very powerful (and, I guess more importantly, convenient) possibilities of graphical debugging.
pass the binary with gdb
gdb <binary>
then set breakpoint to main
gdb) break main
Then run your program in gdb
gdb) run
then break point hits use 'n' or 'next' to step to different lines
gdb) n
Use 's' for stepping into function and 'p' printing var value
Example :
gdb) s <fun_name>
gdb) p x
I would suggest , as a beginner start off with Visual Studio. It has a very good and easy to use debugger. Just create a break point in the line from which you want to start debugging (click on the left bar beside the line or right click and create a break point). Once your break points are set you can just simply run the program in debug mode and the execution of the program will halt in the point where the break was created.
At this point you should be able to view all valuable information about the execution of the program. You can use F10 to continue the execution step or F11 to step inside the execution tree.
The debugger as many other advanced features like break on condition , hit count etc but you can start off with it's basic functionality.
If I compiled a program like this:
gcc -o my-prog -g myprog.c
I could then debug the executable my-prog it like this:
gdb my-prog
The -g option tells gcc to generate full debugging info. Other compilers will have their own versions of this option (e.g. the MSVC cl command has the /Zi option).
Since you're having issues running the gdb on your program, it might be worth checking if it was compiled with debugging info in the first place. The debugging info is usually generated in the same location as where you compiled your program.
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Closed 10 years ago.
Possible Duplicate:
Is there an interpreter for C?
I want to practice C a bit and I would like to have something that allows to write and test C code quickly. I want to have an interpreter with UI where I can write my code and execute it.
Are there any good solutions for that?
The closest solution to what you are looking for seems to be the C shell (CSH) or C Scripting Language (CSL).
Alternatively, have an editor open where you will write your C sample, then have console window where you will execute your favourite C compiler. The idea is to have simple workflow like this:
$ gvim test.c
$ gcc test.c
$ ./a.out
Don't forget, C is not a scripting language.
However, you may find JIT compiler for C, C++, and the likes discussion helpful.
Though "interpreters" per se don't exist (or not practically), I'd advise on using a modern IDE. Eclipse + CDT allows you to have "on the fly compilation", just like in java. Your project is ready to run whenever you are, with reduced latency due to compilation (if you have a decent computer).
For other answers, I advise on NOT using directly gcc test.c. Use a makefile or use at least gcc -Wall -g -o myapp test.c top have additional information during compilation (useful as C has many more pitfalls than python). Please note as well that testis astandard program and that . might not be in your PATH : myapp is a better name than test ;-)
There is Cling. Never used it, so I can't really tell you more, but it looks like what you are looking for.
You might also find other lead in this question: Is there an interpreter for C?
you can take a look at : http://codepad.org/
or the easy way is to create a sh script like :
vim $1 ; gcc $1 ; ./a.out
You can't interpret C++ code as far as I know...
What you could do (and what I do when I quickly need to write some simple things ) is set up a simple make file and open a new file with some simple text editor like Kate that has a console plugin. Then you can write some code and type "make" to see the result of your code in the konsole / whichever shell you are using