LinuxQuestions.org - GCC compiler error while compiling *.c file

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - GCC compiler error while compiling *.c file (https://www.linuxquestions.org/questions/programming-9/gcc-compiler-error-while-compiling-%2A-c-file-914284/)

GCC compiler error while compiling *.c file

Dear Friends,

I write a program in C i.e. Hello.C

When I try to compile it by giving the following command

$ cc Hello.C
oR
$ gcc Hello.C

I always got this error

cc HELLO.C /tmp/ccB6cpfR.o: (.eh_frame+0x12): undefined reference to `__gxx_personality_v0' collect2: ld returned 1 exit status

Please help me to get out of it. Thanks

I guess the compiler thinks your source is C++,
try the same thing with lowercase filename: hello.c

Quote:

Originally Posted by NevemTeve (Post 4527856)

compiler thinks your source is C++,

I never knew that before (.C is treated as .cpp not as .c) but I both tested it and looked it up and you are correct.

ssvirdi, if you have some reason to want to keep the name Hello.C instead of changing it to Hello.c you could compile it with
gcc -xc Hello.C

The -xc option tells gcc the type of the input file is "c". If it knows the type already, it doesn't decide the type based on the extension (the .C).

The confusing error message you got is because the gcc command invokes the linker for a .c program regardless of the type of the input file. So your .C file is compiled as a C++ module but linked as a .c program, resulting in that link time error.

That behavior must seem silly when operating on just one input file. But gcc can compile and link multiple files in one command including mixed language programs. So this behavior that seems silly with one input file makes sense for more complicated commands.

The "case" doesn't make any difference on gcc version 4.5.0 .
I just tried that with a file h.C, there weren't any problems
shown.

But with gcc-4.3.2 it can be reproduced easily:

Code:



$ gcc hello.C -o hello

/tmp/cceGJBdd.o:(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'

collect2: ld returned 1 exit status



$ gcc hello.C -o hello -lstdc++

(works)



$ g++ hello.C -o hello

(works)



$ ln -s hello.C hello.c

$ gcc hello.c -o hello

(works)

so, the crux is to shift to the newer gcc version. ;)

Another option (if you are not root-user, for example) is following the standard: the extension is .c for C-language, not .C

Quote:

Originally Posted by NevemTeve (Post 4533407)

Another option (if you are not root-user, for example) is following the standard: the extension is .c for C-language, not .C

Why is is only an option when you are not root?

The proper solution is to use a lowercase ".c" extension. Uppercase ".C" means C++, so don't use it for C source code.

Quote:

Originally Posted by NevemTeve (Post 4533407)

Another option (if you are not root-user, for example) is following the standard: the extension is .c for C-language, not .C

What does the issue have to do with (not) being 'root' ?

(If you aren't superuser, then you are not supposed to install new versions of gcc, but you can still follow the naming standards and use the extension .c for C-language.)

Quote:

Originally Posted by NevemTeve (Post 4534112)

... If you aren't superuser, then you are not supposed to install new versions of gcc ...

Huh ?

I am routinely compiling from source not as 'root' user more than 370 targets and install them in a non-system directory of mt liking. Even though it's my personal machine and I have root access.

But what does it have to do with a wrong file extension in the first place ?

Quote:

Originally Posted by NevemTeve (Post 4534112)

(If you aren't superuser, then you are not supposed to install new versions of gcc, but you can still follow the naming standards and use the extension .c for C-language.)

But if you are superuser, you should still change it to ".c" instead of ".C", because ".C" is the wrong extension for C code.

(I don't think we should continue this argumentation, because basically we all suggest the same thing: using the correct file-extension.)