Hello!   I am using boost regexp to do string/expression match. I got several dump files that have the same call stack when the crash happends. What my code does  is copying user buffer (containing string to be mached) to an internal allocated buffer and then call boost regexp functions.   From the following result of windbg's "analyze", can you tell what cause the null intrstrucation ptr? I check the memory that contains the string to macht and didn't find any wrong.   Also, btw, where can I find boost pdb?   Thank you.   ==================================================== FAULTING_IP: +0 00000000 ??              ???   EXCEPTION_RECORD:  ffffffff -- (.exr 0xffffffffffffffff) ExceptionAddress: 00000000    ExceptionCode: c0000005 (Access violation)   ExceptionFlags: 00000000 NumberParameters: 2    Parameter[0]: 00000000    Parameter[1]: 00000000 Attempt to read from address 00000000   PROCESS_NAME:  nlca_service.exe   ERROR_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".   EXCEPTION_CODE: (NTSTATUS) 0xc0000005 - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".   EXCEPTION_PARAMETER1:  00000000   EXCEPTION_PARAMETER2:  00000000   READ_ADDRESS:  00000000   FOLLOWUP_IP: nlca_framework+4578a 1004578a 84c0            test    al,al   FAILED_INSTRUCTION_ADDRESS: +0 00000000 ??              ???   NTGLOBALFLAG:  0   APPLICATION_VERIFIER_FLAGS:  0   FAULTING_THREAD:  00000574   BUGCHECK_STR:  APPLICATION_FAULT_NULL_INSTRUCTION_PTR_INJECTED_CRASH   PRIMARY_PROBLEM_CLASS:  NULL_INSTRUCTION_PTR   DEFAULT_BUCKET_ID:  NULL_INSTRUCTION_PTR   LAST_CONTROL_TRANSFER:  from 1004578a to 00000000   STACK_TEXT:  WARNING: Frame IP not in any known module. Following frames may be wrong. 0134fd08 1004578a 0134fde8 00000001 10036e74 0x0 0134fd14 10036e74 00000008 0134fde8 00000002 nlca_framework!boost::re_detail::perl_matcher,std::allocator> ,std::allocator,std::allocator > > >,boost::regex_traits > >::match_all_states+0x9a 0134fd4c 1004578a 0134fde8 0114229c 10046239 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::match_startmark+0x194 0134fd58 10046239 0134fde8 10046370 0112fea4 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::match_all_states+0x9a 0134fd60 10046370 0112fea4 006ba6e0 0134fda8 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::match_prefix+0x39 0134fd78 10049e71 eaa88d5d 0112fea4 006ba6e0 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::find_restart_any+0xe0 0134fda8 10036cc8 eaa88d41 100606e8 0134fde8 nlca_framework!boost::re_detail::abstract_protected_call::execute+0x41 0134fdc8 10046f4a 10046b40 10010cbc eaa88d29 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::protected_call+0x48 0134fdd0 10010cbc eaa88d29 0112fea4 006ba6e0 nlca_framework!boost::re_detail::perl_matcher,std::allocator>,std::allocator,std::allocator > > >,boost::regex_traits > >::find+0xa 0134fe78 100112bb 0112fea4 0114e3c8 0112fea4 nlca_framework!boost::regex_search,std::allocator> ,std::allocator,std::allocator > > >,wchar_t,boost::regex_traits > >+0xac 0134ff24 1001166d 0112fea4 006ba6e0 00000000 nlca_framework!NLCA::ContentAnalysisRPCTask::`scalar deleting destructor'+0x12b 0134ff48 72881657 00000007 0112fea4 0113ff00 nlca_framework!NLCA::ContentAnalysisRPCTask::CloneTask+0x1cd 0134ff98 7288880f 0016b8f0 00000001 00000000 vcomp!_vcomp::ParallelRegion::HandlerThreadFunc+0xd7 0134ffb4 7c80b729 0016b880 00000000 00000000 vcomp!_vcomp::NullAPCFunc+0x7f 0134ffec 00000000 728887d0 0016b880 00000000 kernel32!BaseThreadStart+0x37     SYMBOL_STACK_INDEX:  1   SYMBOL_NAME:  nlca_framework+4578a   FOLLOWUP_NAME:  MachineOwner   MODULE_NAME: nlca_framework   IMAGE_NAME:  nlca_framework.dll   DEBUG_FLR_IMAGE_TIMESTAMP:  49950ed6   STACK_COMMAND:  ~11s; .ecxr ; kb   FAILURE_BUCKET_ID:  NULL_INSTRUCTION_PTR_c0000005_nlca_framework.dll!Unknown   BUCKET_ID:  APPLICATION_FAULT_NULL_INSTRUCTION_PTR_INJECTED_CRASH_NULL_IP_nlca_framework+4578a   Followup: MachineOwner ---------  Heidi