Changing a function signature in DEF file

Question

I'm changing signature of a function which will be exported in dll.

DEF file:

...
??0CLimitOrderBase@Base@@QEAA@H@Z
?foo@CLimitOrderBase@Base@@UEAAHAEAVCLimitInfo@2@@Z
...

Code will change from

namespace Base {

class CLimitOrderBase : public CLimit
{
    ...
    virtual BOOL foo(CLimitInfo &limitInfo);
    ...
};

to

virtual BOOL foo(CLimitInfo &limitInfo, bool bCheck = false);

How do I get the new mangled name to change in the DEF file?

Why not to declare your class as `__declspec(dllexport)` and forget about manually exporting functions having mangled names? — Serge Rogatch, Jul 07 '15 at 07:57
You change it with a text editor. Use the linker's .map file to see the new name. — Hans Passant, Jul 07 '15 at 08:09

score 1 · Answer 1 · answered Jul 07 '15 at 08:05

Add the following to a header file which every other header file from your DLL includes (renaming YOURDLL with something meaningful):

#ifdef YOURDLL_EXPORTS
#define YOURDLL_API __declspec(dllexport)
#else
#define YOURDLL_API __declspec(dllimport)
#endif

Then declare your exported classes as in this example:

class YOURDLL_API CLimitOrderBase : public CLimit
{
    ...
    virtual BOOL foo(CLimitInfo &limitInfo);
    ...
};

Finally, define YOURDLL_EXPORTS in your DLL project (Preprocessor Definitions field under Properties->C/C++->Preprocessor). This way you wouldn't need manual editing of .DEF file.

score 0 · Answer 2 · edited May 23 '17 at 12:13

0

Using dllexport is a good idea, but currently I'm just changing one function of a existing big DEF file, and .def vs _declspec(dllexport) is beyond this topic.

Thanks for the comment from Hans Passant, I finally figured out how to get mangled C++ function name from Visual Studio (For g++ please refer to this answer.)

Generate .map file:
- In VS, open the project's Property Pages dialog box
- Click Linker folder
- Click Debug property page
- Modify Generate Map File property.
Rebuild the project.
Open generated .map file, search for the function name.
Copy the new mangled name to .def file

edited May 23 '17 at 12:13

Community

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answered Jul 08 '15 at 01:01

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You can also use `dumpbin /exports` on the DLL to get a list of all the exported names. – Michael Burr Jul 08 '15 at 01:13

Changing a function signature in DEF file

2 Answers2