Hi All, I'm working on a OpenBSD 4.9 system, and I've receiving multiple "error: template with C linkage" errors. OpenBSD uses a 4.2.1 compiler. $ gcc --version gcc (GCC) 4.2.1 20070719 Copyright (C) 2007 Free Software Foundation, Inc. A typical output is: g++ -g3 -ggdb -O0 -pipe -fsigned-char -fmessage-length=0 -Woverloaded-virtual -Wreorder -Wformat=2 -Wformat-security -Wno-unused -fvisibility=hidden -fstack-protector -I. -I./esapi -I./deps -I/usr/local/include -fpic -c src/codecs/HTMLEntityCodec.cpp -o src/codecs/HTMLEntityCodec.o In file included from /usr//include/cryptopp/misc.h:4, from ./esapi/crypto/Crypto++Common.h:24, from src/codecs/HTMLEntityCodec.cpp:12: /usr//include/cryptopp/cryptlib.h:99: error: template with C linkage /usr//include/cryptopp/cryptlib.h:247: error: template with C linkage /usr//include/cryptopp/cryptlib.h:254: error: template with C linkage /usr//include/cryptopp/cryptlib.h:261: error: template with C linkage /usr//include/cryptopp/cryptlib.h:268: error: template with C linkage /usr//include/cryptopp/cryptlib.h:293: error: template with C linkage /usr//include/cryptopp/cryptlib.h:698: error: template with C linkage The first offending line in cryptlib.h is: // VC60 workaround: using enums as template parameters causes problems template <typename ENUM_TYPE, int VALUE> struct EnumToType { static ENUM_TYPE ToEnum() {return (ENUM_TYPE)VALUE;} }; I've tried adding '-x c++' to force c++ in the files. I have also audited Crypto++ and my code for a 'dangling extern "C"'. Crypto++ uses extern "C" about 13 times (a typical usage is below), and I don't use it. #ifdef CRYPTOPP_X64_MASM_AVAILABLE extern "C" { void Rijndael_Enc_AdvancedProcessBlocks(void *locals, const word32 *k); } #endif I built Crypto++ from sources (it compiled and self-tested OK) and then installed it via makefile. So I'm surprised to find Crypto++ is [supposedly] causing problems. I found a few bug reports relating to a spurious error, but they appeared to be for platforms other than x86/x64. Any ideas? Jeff