My Tech Notes

Well, this is not really a trick but rather a trivial remark, but Visual Studio entertains some peculiar notion of "default libraries", which means, basically, that object file "knows" which basic system libraries like LIBCMT.LIB (basic C multithreaded library) or LIBCMTD.LIB (debugging version). That means that if you have certain 3-rd party or external libraries which you only have available to you in "non-debugging" version, and when try to link them with your project in "Debug" configuration, linker may want to include both LIBCMT.LIB and LIBCMTD.LIB, creating multiply-defined symbols and failing the build.

For some reason, problem (for me) only appears when I try to use STL library, which then causes diagnostics like this:

LIBCMTD.lib(dbgheap.obj) : error LNK2005: __heap_alloc already defined in LIBCMT.lib(malloc.obj)
LIBCMTD.lib(dbgheap.obj) : error LNK2005: __recalloc already defined in LIBCMT.lib(recalloc.obj)
LIBCMTD.lib(dbgheap.obj) : error LNK2005: __msize already defined in LIBCMT.lib(msize.obj)
LIBCMTD.lib(malloc.obj) : error LNK2005: _V6_HeapAlloc already defined in LIBCMT.lib(malloc.obj)
LIBCMTD.lib(dbghook.obj) : error LNK2005: __crt_debugger_hook already defined in LIBCMT.lib(dbghook.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: __get_sbh_threshold already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: __set_sbh_threshold already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: __set_amblksiz already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: __get_amblksiz already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_heap_init already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_find_block already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_free_block already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_alloc_block already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_alloc_new_region already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_alloc_new_group already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_resize_block already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_heapmin already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_heap_check already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(sbheap.obj) : error LNK2005: ___sbh_pHeaderDefer already defined in LIBCMT.lib(sbheap.obj)
LIBCMTD.lib(isctype.obj) : error LNK2005: __isctype_l already defined in LIBCMT.lib(isctype.obj)
LIBCMTD.lib(isctype.obj) : error LNK2005: __isctype already defined in LIBCMT.lib(isctype.obj)

The solution is to add option "/NODEFAULTLIB:LIBCMT" to the linker; this can (only) be done via manually editing linking options in project configuration:

Labels: visual studio, windows

# posted by Kostya @ 8:51 PM