broberts@kingcong.uwaterloo.ca (Brent Robertson) writes:

>I'm trying to integrate some C++ code into an existing C app, My C++ code
>along with the other C code compiles fine.  Linking is another kettle of fish
>however:

You will need to use `extern "C"' as described in the comp.lang.c++ FAQ
list.

>Undefined                       first referenced
> symbol                             in file
>cout                                code/rt.o
>BuildSymbol__FPcPdT1iii             code/rt.o
>pop__Fv                             code/rt.o
>cerr                                code/rt.o

The undefined `cout' and `cerr' are probably because you're not
linking libg++ in.  You need to link using `g++' rather than `gcc',
or use the `-lg++' option at the end of the link command.

The other undefined symbols, which c++filt (from the GNU binutils
distribution) decodes as

 BuildSymbol(char *, double *, double *, int, int, int)
 pop(void)

are probably C functions which need to be declared as `extern "C"'.

>But I've got iostream.h and a bunch of other includes there...  What am I
>doing wrong?

#including the header files does not necessarily ensure that the appropriate
libraries will be linked in.

This is a GNU C++ issue rather than a C++ standards issue,
so I'm cross-posting and redirecting followups to gnu.g++.help.

--
Fergus Henderson - fjh@munta.cs.mu.oz.au

I'm trying to integrate some C++ code into an existing C app, My C++ code
along with the other C code compiles fine.  Linking is another kettle of fish
however:

Undefined                       first referenced
 symbol                             in file
cout                                code/rt.o
BuildSymbol__FPcPdT1iii             code/rt.o
pop__Fv                             code/rt.o
cerr                                code/rt.o

[ rt.C is the sole C++ source file in the entire app ]

But I've got iostream.h and a bunch of other includes there...  What am I
doing wrong?
--

Brent :)
--------------------------------------------------------------------------------
broberts@kingcong.uwaterloo.ca                      University of Waterloo
                                             Electrical and Computer Engineering
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