CODEWITHSUNDEEP
c++cgccg++
bryan sammon
bryan sammon

Reputation: 7441

gcc - linking multiple c files to a c++ file

How do you link 2 c library files, to a c++ file?

Right now I am doing this:

> gcc -c file1.c (this works fine) 

> gcc -c file2.c ( this works fine)

> g++ -c myc++file.cpp (this works fine)

> g++ -o program myc++file.o file1.o file2.o

-> I get an error on this last one saying that their is a undefined reference to a function in myc++file.o, but that function is defined in file2.o. Something is wrong, but I just cant figure it out.

Any ideas?

Upvotes: 0

Views: 535

Answers (2)

ugoren
ugoren

Reputation: 16451

You need to use extern "C" on the function's declaration.
When C++ sees an external function, it mangles the name, to identify the parameter and return value types. When trying to link it with C code, the names don't match.
extern "C" tells C++ not to mangle the name, so it would successfully link with C code.

Upvotes: 2

asaelr
asaelr

Reputation: 5456

Is this function static?

Did you use extern "C" in myc++file.cpp?

if the answers is no and yes, show us some code.

(By the way, try to check using nm if that function is really in file2.o)

Upvotes: 3

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