CODEWITHSUNDEEP
c++visual-c++linkerzlibunresolved-external
fogbit
fogbit

Reputation: 2063

protocol buffers + zlib = unresolved external symbol

My program (VS 2010) uses Google Buffer Protocol compiled with HAVE_ZLIB option enabled. I compiled the latest version of zlib and added .lib in my project, but during linking i still got

1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol _inflateEnd 1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol inflateInit2 1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol _inflate 1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol deflateInit2 1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol _deflate 1>libprotobuf.lib(gzip_stream.obj) : error LNK2001: unresolved external symbol _deflateEnd

I used dumpbin.exe /all zlib.lib, it says:

File Type: LIBRARY

....

245 public symbols

....

 4DBE __imp__inflateInit2_@16
 4DBE _inflateInit2_@16

also there are other unresolved symbols in this list.

What's wrong then? Why does the linker can't find these functions?

upd: after recompiling zlib now it's __imp__inflateInit2_@4

Upvotes: 3

Views: 3505

Answers (1)

user1438233
user1438233

Reputation: 1233

zlib functions are defined as ZEXPORT. if ZLIB_WINAPI is defined, then ZEXPORT is defined as __stdcall, else it has no value and all zlib function are defined by default to __cdecl.

When i compiled zlib in VS2015, ZLIB_WINAPI was defined in zlib project, and in my c++ project ZLIB_WINAPI was not defined. so my project is looking for __cdecl functions in the zlib .lib file, and the zlib .lib file is compiled as __stdcall.

to fix that, you need to tell the compiler in your project that the zlib .lib file uses __stdcall call convention.

do is by using:

#define ZLIB_WINAPI

before

#include "....\zlib.h"

in your project

Upvotes: 2

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