visual c++ - C++ std::string Parameter is <Bad Ptr> -

i'm using visual studio 2010.

i have class following constructor:

cvideoannotation::cvideoannotation(std::string aport, dword abaudrate) 

i create instance of cvideoannotation follows:

cvideoannotation cvideoannotation("com3", cbr_9600); 

'cbr_9600' macro resolves 9600.

down in constructor, abaudrate 9600 expected. however, aport not passed properly. when hover cursor on it, intellisense gives value of <bad ptr>.

does have thoughts on why string not pass properly?

thanks, dave

as update original question, i'm adding assembly code constructor call , population of locals once inside constructor.

   cvideoannotation cvideoannotation("com3", cbr_9600); 0041177d  push        2580h   00411782  sub         esp,20h   00411785  mov         ecx,esp   00411787  mov         dword ptr [ebp-174h],esp   0041178d  push        offset string "com3" (4198c8h)   00411792  call        std::basic_string<char,std::char_traits<char>,std::allocator<char> >::basic_string<char,std::char_traits<char>,std::allocator<char> > (41131bh)   00411797  mov         dword ptr [ebp-17ch],eax   0041179d  lea         ecx,[ebp-11h]   004117a0  call        dword ptr [__imp_cvideoannotation::cvideoannotation (41d4dch)]   004117a6  mov         dword ptr [ebp-180h],eax   004117ac  mov         dword ptr [ebp-4],0        cvideoannotation::cvideoannotation(std::string aport, dword abaudrate) { 100137f0  push        ebp   100137f1  mov         ebp,esp   100137f3  push        0ffffffffh   100137f5  push        offset __ehhandler$??0cvideoannotation@@qae@v?$basic_string@du?$char_traits@d@std@@v?$allocator@d@2@@std@@k@z (1001dc82h)   100137fa  mov         eax,dword ptr fs:[00000000h]   10013800  push        eax   10013801  sub         esp,164h   10013807  push        ebx   10013808  push        esi   10013809  push        edi   1001380a  push        ecx   1001380b  lea         edi,[ebp-170h]   10013811  mov         ecx,59h   10013816  mov         eax,0cccccccch   1001381b  rep stos    dword ptr es:[edi]   1001381d  pop         ecx   1001381e  mov         eax,dword ptr [___security_cookie (10026090h)]   10013823  xor         eax,ebp   10013825  mov         dword ptr [ebp-10h],eax   10013828  push        eax   10013829  lea         eax,[ebp-0ch]   1001382c  mov         dword ptr fs:[00000000h],eax   10013832  mov         dword ptr [ebp-18h],ecx   10013835  mov         dword ptr [ebp-84h],0   1001383f  mov         dword ptr [ebp-4],0   

if implementing cvideoannotation in separate dll having know issue of crossing dll boundaries when using stl containers. verify case create new constructor taking const char* instead of std::string , try..

another thing, instead of std::string prefer use const std::string&