gcc help please

tyler_durden · Post by **tyler_durden** » Fri Sep 28, 2001 8:14 pm

i am working on a school project for my operating sytems class. i dont have alot of expierence working with gcc. Our project is to write a shell in unix. our prof gave us a file that will parse the input, we then have to run the commands. everything works fine on the solaris machines at school. when i go to make the file i get the following error. how can i force the compilation?

make mysh
gcc -o mysh mysh.o parse.o
collect2: ld terminated with signal 11 [Segmentation fault]
mysh.o: In function `main':
mysh.o(.text+0x28): the `gets' function is dangerous and should not be used.
make: *** [mysh] Error 1

is there something i can run to overide that check.

poop · Post by **poop** » Fri Sep 28, 2001 9:28 pm

Well, techincally, you should try to use fgets since gets is a security hazard. ;)

It doesn't look like gcc is failing, it is the linker (ld). The linker will essentially take mutliple binary files as input and link them together with common symbol tables and such so they make a nice, monolithic executable file. gcc actually calls ld to link the files you specify. It uses a set of default arguments.

Thus, you need to send a command to gcc in order for gcc to tell ld to ignore the warning. I don't know the command line switch that you need, but I will search.

Try man ld and see what your system says about forcing a link. It will most likely be in the 'Options' heading, and will be proceeded with a '-b'. So, if you want the option noquiet, you type: gcc -bnoquiet -o >output< >input list<

Try "-bnoerrmsg" though I am not sure it will work. This option disables error messages from the linker.

tyler_durden · Post by **tyler_durden** » Sat Sep 29, 2001 12:25 am

i fixed the problem witht he gets, just replaced it with fgets. but i am still gettting the

collect2: ld terminated with signal 11 [Segmentation fault]

any ideas?

poop · Post by **poop** » Sat Sep 29, 2001 12:52 pm

hrm... if you want, e-mail me your makefile and I will take a look at it.

I might be able to figure out what is going on.

tyler_durden · Post by **tyler_durden** » Sat Sep 29, 2001 9:55 pm

i figured out the problem, our prof gave us the make file, it compiles the our file, and the file he gave us into .o files (object files) then it links those into a single output. the linker keeps throwing an error. i just compiled the code using gcc. theys seem to compile, tbey arn't running right, even though they work fine on the schools spark machines using gcc. so i don't know what it is.

poop · Post by **poop** » Sat Sep 29, 2001 11:22 pm

So he gave you the source and pre-made output files? What kind of machine are you trying to compile on? You mention it works fine on a Sun Sparc (Solaris, I assume). If you are trying to use DJGPP, then I can see where you might have some probs. But as long as you are using properly configured GNU tools on a properly configured *nix system, I don't know why the code will work on one machine adn not another.

I also assume you are using POSIX commands and stdio for most of your stuff... Hrm... C is one of those things that is nearly impossible to help someone with without being there. Sorry I cannot help too much.