Visual Studio 2010 LibTomCrypt Build or Library Linking Error - c++

Question

Using the the entire LibTomCrypt source, I've built a library file with Visual Studio 2010 which compiles without issue. However, when creating a simple test console application that links the with TomCrypt library, I receive a linker error for the following code:
Test Code:
#include <stdio.h>
#include <tomcrypt.h>
int main()
{
int Cipher;
register_cipher( &aes_desc );
Cipher = find_cipher( "aes" );
if( Cipher != CRYPT_OK )
return 0;
printf( "Cipher name: %s\n", cipher_descriptor[ Cipher ].name );
unregister_cipher( &aes_desc );
return 0;
}
Linker Error:
error LNK1120: 1 unresolved externals
error LNK2001: unresolved external symbol _aes_desc
Interestingly, the debug library build works perfectly with the test code. It is the release build of tomcrypt.lib that seems to be missing some symbols.
Now I'm not new to building and using library files, but I'm wondering, are there some specific compiler flags or precautions I can make to build the library in release mode and have it link correctly in my test program? Could it be that the static aes_desc structure, defined in the LibTomCrypt code, be missing from the release build of the library by way of some compiler optimization?
I hope someone can offer some insight for myself and anyone else experiencing this issue.

Answer 1

I just ran into a related issue today. The project configs for visual studio include custom steps for building aes.c, but only cover Debug builds. Once I made comparable provisions for Release builds, all was well.
Open the Visual Studio 2010 project in text editor and replace the custom build steps with the ones below. This will also fix some warnings for the Debug build:
<CustomBuild Include="src\ciphers\aes\aes.c">
<Command Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">cl /nologo /MTd /W3 /Gm /EHsc /ZI /Od /I "src\headers" /I "..\libtommath" /D "_DEBUG" /D "LTM_DESC" /D "WIN32" /D "_MBCS" /D "_LIB" /D "LTC_SOURCE" /D "USE_LTM" /Fp"Debug/libtomcrypt.pch" /Fo"Debug/" /Fd"Debug/" /FD /RTC1 /c %(FullPath)
cl /nologo /DENCRYPT_ONLY /MTd /W3 /Gm /EHsc /ZI /Od /I "src\headers" /I "..\libtommath" /D "_DEBUG" /D "LTM_DESC" /D "WIN32" /D "_MBCS" /D "_LIB" /D "LTC_SOURCE" /D "USE_LTM" /Fp"Debug/libtomcrypt.pch" /Fo"Debug/aes_enc.obj" /Fd"Debug/" /FD /RTC1 /c %(FullPath)</Command>
<Outputs Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Debug/aes.obj;Debug/aes_enc.obj;%(Outputs)</Outputs>
</CustomBuild>
<CustomBuild Include="src\ciphers\aes\aes.c">
<Command Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">cl /nologo /MT /W3 /O2 /I "src\headers" /I "..\libtommath" /D "NDEBUG" /D "LTM_DESC" /D "WIN32" /D "_MBCS" /D "_LIB" /D "LTC_SOURCE" /D "USE_LTM" /Fp"Release/libtomcrypt.pch" /Fo"Release/" /Fd"Release/" /FD /c %(FullPath)
cl /nologo /DENCRYPT_ONLY /MT /W3 /O2 /I "src\headers" /I "..\libtommath" /D "NDEBUG" /D "LTM_DESC" /D "WIN32" /D "_MBCS" /D "_LIB" /D "LTC_SOURCE" /D "USE_LTM" /Fp"Release/libtomcrypt.pch" /Fo"Release/aes_enc.obj" /Fd"Release/" /FD /c %(FullPath)</Command>
<Outputs Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Release/aes.obj;Release/aes_enc.obj;%(Outputs)</Outputs>
</CustomBuild>