VC5: .c vs .cpp Compiling/Linking: Unresolved Externals

Posted on 1998-08-12
Medium Priority
Last Modified: 2010-04-10
I have a .c file which compiles and links fine. When I compile and link this file with the /Tp option to specify it to be compiled as a C++ file the link fails with the error: LNK2001 unresolved external symbol. The .lib which contains the implementation of the function I am trying to use matches with a .dll which was written in visual basic. Any ideas?
Question by:wewesb

Accepted Solution

snoegler earned 60 total points
ID: 1170036
The point is that c++ function names get 'mangled' when building the .obj files.
'dumpbin' your c++ object file and your c object file and compare them, then you'll see
what i mean. To avoid this, declare the functions with like this:
void _declspec("C") my_func()
This tells the compiler even if compiling c++ files to use the 'c' naming scheme.

Author Comment

ID: 1170037
Ah yes, that led me to a solution. I first tried void _declspec("C") my_func() but I got a syntax error complaining about "string". I changed the syntaxt to "C" void my_func() and it compiled and linked fine. Thanks!

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