I have written a very simple C program to print "Hello World" in my Notepad text editor and saved it as test1.exe. I opened my cmd and ran the file test.exe and the received error is as follows:
The NTVDM CPU has encountered an Illegeal instruction. CS:0607
IP:0103 OP:63 6c 75 64 65 Choose 'Close' to terminate the application.
You need to save the file as test.c and then compile it to test.exe. The exact details of how you compile it will depend on what C compiler you have installed, but for cygwin or MinGW it would be:
$ gcc -Wall test.c -o test.exe
If you don't have a compiler installed yet and just want to quickly try running a small C program then a further alternative is to use a site such as codepad.org or ideone.com where you can type (or paste) your code and run it online.
A few things to help you learn C in an easier manner:
First, you say you wrote it in Notepad. Bad choice for learning C. Notepad does not support Syntax highlighting.
Second, C needs to be compiled, on windows you have a few choice for compiler, the first would be MinGW which is Free.
Third, and IDE that is MinGW aware and C syntax aware is also needed. Geany is simple enough but is very smart and full of sweets.
Finally, see the tutorial here, how to get them all working: geany+mingw on windows.
One more thing, totally unrelated to C, or maybe it does.
I bluntly assume that C is your first programming experience, or that you are still doing first steps in programming.
C as a first language is VERY BAD. It is not forgiving, and most compilers pass things, but the code will crash, not letting you know what you did wrong.
Consider learing other languages first, a few good choices would be:
Python
Lua
Ruby
If you need a compiler and environment for C, I'd go with Visual Studio Express instead of the other suggestions. It's much more comfortable and offers a fuller Windowsy feel. And it's also free.
Related
I've recently migrated from Windows 7 to Linux (Ubuntu 14.04) and want to compile a C program that I made. The program worked perfectly under Codeblocks 12.11 using GNU GCC compiler's basic settings. When compiling under linux under Codeblocks 13.12 using GNU GCC compiler's basic settings, I get the following error messages:
undefined reference to __mingw_vprintf
undefined reference to __chstk.ms
undefined reference to _fopen
... and so on with fscanf, malloc, etc...
I'm new to Linux and I am not used to C coding, or even programming in general. Does someone have an idea about what's going on?
you have three separate problem going on here.
(1) for _fopen, Microsoft has a nasty habit of renaming all the POSIX functions so they start with an underscore, while your Linux distribution is looking for the standard POSIX name, i.e. fopen. Welcome to the wonderfully frustrating world of cross-platform development :). On solution would be to add something along these lines:
#ifdef __WIN32
#define fopen _fopen
#endif
This in effect says, if compiling on a windows machine (which typically has __WIN32 defined as a preprocessor define; and if it is not you can always make sure that it is) replace every occurrence of fopen with _fopen. The preprocessor will do this for you.
(2) for __mingw_vprintf, I've never seen this function but from the name I would surmise that it is an implementation of vprintf specific to mingw. I personally would rewrite my code to stick with the standard C function vprintf. You can read the manual page for vprintf here; and the MSDN information can be found here. Again notice that many of the Microsoft provide functions have an underscore prepended to the name. You can do something like what you did in case (1) above.
N.B. Actually if I were to rewrite the program I would use C++ IO-streams, but I am sticking to a pure C answers.
(3) for __chstk.ms, again I've never seen this function. My suspicion is that it is something inserted into your code to perform stack checking to help prevent stack-based exploits. To the best of my knowledge there is no way you are going to get that to work on a Linux machine.
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Possible Duplicate:
How are gcc/g++ bootstrapped?
I would like to know how gcc is compiled as we all know it is written in C.
Did they used some other compiler to come up with gcc?
If so, can I use the same compile to compile my C program?
There is no chicken and egg here. glibc is compiled with the compiler you are using.
That compiler was first compiled with a previous version of the same compiler. Then it can compile itself as well.
The real chicken-and-egg problem was solved in the 1950's when someone had to write the world's first compiler. After that, you can use one compiler to compile the next one.
There are two basic ways to build a new compiler:
If you're writing a new compiler for an established language like C, use an existing compiler from a different vendor to build your new compiler. For example, you could use the C compiler shipped with HP-UX to build gcc.
If you're writing a compiler for a new language, start by implementing a very simple compiler in a different language (the first C compiler was written in PDP-11 assembler). This initial compiler will only recognize a small subset of the target language; basically enough to do some file I/O and some simple statements. Write a new compiler in the target language subset and build it with your first compiler. Now write a slightly more capable compiler that can recognize a larger subset of the target language, and build it with the second compiler. Repeat the process until you have a compiler capable of recognizing the full target language.
They did not use some other compiler. You can write a C program that doesn't use glibc by simply telling the compiler not to use it. So something like this:
gcc main.c -nostdlib
This is an interesting question. I think you are wondering in what language is written a compiler of a new language, aren't you? Well, if we had only Assembly language (for instance,x86), the only way to write a C compiler would be in Assembly language. Later, we could write a better, yet more powerful compiler written in C by using our assembly-written compiler, and so on...
An the question arises: how did the early programmers write the first assembly compiler? My father told me: by manually entering the 1's and 0's! :-)
I have created my very own (very simple) byte code language, and a virtual machine to execute it. It works fine, but now I'd like to use gcc (or any other freely available compiler) to generate byte code for this machine from a normal c program. So the question is, how do I modify or extend gcc so that it can output my own byte code? Note that I do NOT want to compile my byte code to machine code, I want to "compile" c-code to (my own) byte code.
I realize that this is a potentially large question, and it is possible that the best answer is "go look at the gcc source code". I just need some help with how to get started with this. I figure that there must be some articles or books on this subject that could describe the process to add a custom generator to gcc, but I haven't found anything by googling.
I am busy porting gcc to an 8-bit processor we design earlier. I is kind of a difficult task for our machine because it is 8-bit and we have only one accumulator, but if you have more resources it can became easy. This is how we are trying to manage it with gcc 4.9 and using cygwin:
Download gcc 4.9 source
Add your architecture name to config.sub around line 250 look for # Decode aliases for certain CPU-COMPANY combinations. In that list add | my_processor \
In that same file look for # Recognize the basic CPU types with company name. add yourself to the list: | my_processor-* \
Search for the file gcc/config.gcc, in the file look for case ${target} it is around line 880, add yourself in the following way:
;;
my_processor*-*-*)
c_target_objs="my_processor-c.o"
cxx_target_objs="my_processor-c.o"
target_has_targetm_common=no
tmake_file="${tmake_file} my_processor/t-my_processor"
;;
Create a folder gcc-4.9.0\gcc\config\my_processor
Copy files from an existing project and just edit it, or create your own from scratch. In our project we had copied all the files from the msp430 project and edited it all
You should have the following files (not all files are mandatory):
my_processor.c
my_processor.h
my_processor.md
my_processor.opt
my_processor-c.c
my_processor.def
my_processor-protos.h
constraints.md
predicates.md
README.txt
t-my_processor
create a path gcc-4.9.0/build/object
run ../../configure --target=my_processor --prefix=path for my compiler --enable-languages="c"
make
make install
Do a lot of research and debugging.
Have fun.
It is hard work.
For example I also design my own "architecture" with my own byte code and wanted to generate C/C++ code with GCC for it. This is the way how I make it:
At first you should read everything about porting in the manual of GCC.
Also not forget too read GCC Internals.
Read many things about Compilers.
Also look at this question and the answers here.
Google for more information.
Ask yourself if you are really ready.
Be sure to have a very good cafe machine... you will need it.
Start to add machine dependet files to gcc.
Compile gcc in a cross host-target way.
Check the code results in the Hex-Editor.
Do more tests.
Now have fun with your own architecture :D
When you are finished you can use c or c++ only without os-dependet libraries (you have currently no running OS on your architecture) and you should now (if you need it) compile many other libraries with your cross compiler to have a good framework.
PS: LLVM (Clang) is easier to port... maybe you want to start there?
It's not as hard as all that. If your target machine is reasonably like another, take its RTL (?) definitions as a starting point and amend them, then make compile test through the bootstrap stages; rinse and repeat until it works. You probably don't have to write any actual code, just machine definition templates.
I'm want to learn C programming with K&R using XCode, but I can't even get the Hello World to work right - it's giving me errors it shouldn't, I guess because it's being very technical. Can I get XCode to relax on requirements? Would greatly appreciate some advice! Thanks.
Xcode Bah! Just compile from the command line:
gcc myfile.c -o myfile
You don't need Xcode, but if you want to ... Xcode has hello world built in. Make a new project "Command Line Utility", "Standard Tool", give it a name, have a look in "Source", and you'll see the Hello World program:
#include <stdio.h>
int main (int argc, const char * argv[]) {
// insert code here...
printf("Hello, World!\n");
return 0;
}
Click "Build and Run" and it goes, you see:
Running…
Hello, World!
Debugger stopped.
Program exited with status value:0.
I will agree with ergosys above. Xcode is realistically made for Objective-C coding, and even its "Command Line Utility" template is sheer overkill. Anything in K&R will compile flawlessly with
gcc -Wall filename.c
except maybe some of the more advanced stuff. K&R doesn't go into object compiling or linking extensively, since it's only meant to teach you the language. Grasp compilation though, and learning C will be much easier. I much prefer using Makefile's or gcc/g++ than IDE's like Xcode or Eclipse.
I'm gonna assume that XCode is demanding Ansi Standard C, while you are using an early edition of the K&R book, whch still uses the old style.
Unless you are doing this just so you can interprete some ancient C code, don't bother with the old style. Use the Ansi Standard syntax.
Honestly, XCode is way more than you need if using K&R. K&R is about basics, XCode is about making you pull your hair out.
I actually prefer to use the command line instead of an IDE on the Mac.
At least for K&R, using the command line is the way you want to go. Try:
gcc -o outputfile code.c
If you want to get into iPhone/iPod or Cocoa applications, then use Xcode. But more times than most, XCode is overkill and will probably just slow you down.
As I said in my comment, you shouldn't see an error from Xcode with the hello world program from K&R. You might be seeing some warnings, or you have mistyped something. Remember to select the correct language for compiling (you want C, of course).
Can I get XCode to relax on requirements?
In general, you want the compiler to be able to warn you for things that it thinks are not "right". In some cases, the warnings are harmless, and can be turned off, but in most of the cases, the warnings expose issues with your program. I like compiling my code with the maximum warnings enabled for example, because it saves me a lot of time later.
If you are getting errors, you should post (copy-paste) your code here.
Finally, look at the errata page for K&R. It has some bug fixes or corrections, but nothing for hello world.
(It could be that you're using the first edition of the book, in which case you shouldn't use that book to learn C.)
I know there are many tutorials out there for getting started in C. However Its hard for me to apply the knowledge. The way I've always started out in languages is by writing scripts. Of course C is not a scripting language.
My question isn't so much about learning C as much as it is about how to get started applying C. Great I can write a temperature converter or a text-based rpg. Maybe its because in python I just write up the code in somefile.py and chmod +x somefile.py && somefile.py . I do not really have an equivalent process for C. Every time I read about C its a different compiling process with different flags. Can someone just give me some definite direction on best ways to apply C when you already work with higher-level dynamic scripting languages?
Btw. .. I'm asking about C and not C++.
I usually am on either OpenSuse 11 or Ubuntu 9.04 . "What compiler do i use" is part of the problem. In python there is no choice its just "python somefile.py" same with php or ruby. I didn't know there were choices.
write w.c
#include <stdio.h>
int main(int argc, char *argv[]) {
int i;
for (i = 0; i < argc; ++i) {
printf("Param %d is '%s'\n", i, argv[i]);
}
return 0;
}
and compile with
gcc -Wall -o w w.c
run
./w
As rogeriopvl wrote in a comment, the compilation process is really simple. Just write up the code in somefile.c and
gcc -o somefile somefile.c && ./somefile
(if you're using GCC, and if not, your compiler of choice can probably be invoked similarly) Unless/until you start getting into more complicated projects, it's barely any more complicated than a scripting language. (Well... okay, you may need to link some libraries, once you get beyond the basics. But still, not a huge deal.)
In fact, I did write myself a little shell script that allows me to use C as a scripting language. But the process for setting it up is a little more complicated than what you may want to get into at this stage - it's simpler to just run the compiler each time. Still, if you're interested, I can look up the directions (for Linux) and put them here.
C code needs to be compiled before the program can be run. The exact process is different depending on which platform and compiler you are working on.
For the most part, using an IDE (such as Visual studio, Eclipse, MonoDevelop, and a bunch of others) will do the nasty work for you so that you just have to press a button or click an icon. Download one of these
I asked myself this question when I was learning C. The problem here, if I can say this is a problem, is that C can be used in a broad range of applications and in a broad range of environments, which one with its own IDEs or compilers and libraries. Some examples where you can use C for real staff.
Embedded software. In this case you will probably use some lib.
Network programming (take a look at this book.
Device driver development.
Libraries (both for Linux/Windows and other OSs)
Well this list is endless.
O don't know if I help you with this question. If you give more details about what are you interested in, could be helpful
Good luck
The best advice I can give here is find a topic you're interested in, see if you can make a program to do what you want/assist in doing what you want/adding functionality to the interest of choice, and start coding.
This gives the bonus of doing something you're interested in, and at the same time making something that directly influences it. It should give the motivation to keep steaming onward with the learning process.
I'm working with C a lot at the moment with Linux Kernel modules and am relatively new to C. I've found this rewarding which I think is what's important for this sort of hobby 'temperature converter or a text-based rpg' type programming.
I also struggle finding an application of programming skills. Balance of challenge and reward is important I think.