c++ - SHFileOperation cannot remove folder -


i writing c++ custom action wix called during installation remove leftovers installed installer. consider following code:

uint __stdcall deleteresidue(msihandle hinstall) {     hresult hr = s_ok;     uint er = error_success;     lpwstr lpfolderpath = null;     std::wstring temp;     shfileopstruct shfile;      hr = wcainitialize(hinstall, "deleteresidue");     exitonfailure(hr, "failed initialize");      hr = wcagetproperty(l"lpcommappdatafolder",&lpfolderpath);     exitonfailure(hr, "failure in finding common app data folder");      temp = std::wstring(lpfolderpath);     temp+=l"\0\0";      //stop lpa , lpa monitor service. delete residue.     wcalog(logmsg_standard, "doing delete residue");      zeromemory(&shfile, sizeof(shfile));     shfile.hwnd = null;     shfile.wfunc = fo_delete;     shfile.pfrom = temp.c_str();     shfile.fflags = fof_allowundo | fof_noconfirmation | fof_noerrorui;     bool res = directoryexists(lpfolderpath);     if(res)     {         wcalog(logmsg_standard, "the directory exist");         int result = shfileoperation(&shfile);         if(!result)             wcalog(logmsg_standard, "the directory should have deleted now");         else             wcalog(logmsg_standard, "the directory not deleted.error code %d", result);     }            else     {         wcalog(logmsg_standard, "it seems installed folder no more there");     }    lexit:     er = succeeded(hr) ? error_success : error_install_failure;     return wcafinalize(er); }

in above code, c:\programdata inlpcommappdatafolder. doc states pfrom should double null terminated. return value of code 0x2 i.e. error_file_not_found. wrong in code above?

you not double nul terminating pfrom.

you have standard string (which includes null terminator when call .c_str() on it).

temp = std::wstring(lpfolderpath);

you concatenate empty string onto it:

temp+=l"\0\0";

this leaves original string unchanged. because std::string::operator+(const wchar_t*) takes null terminated string. fact have 2 nulls immaterial reads first null. doesn't add null you've given empty string , result of concatenating empty string else no-op.

there's few ways solve this, easiest change

temp+=l"\0\0";

to

temp.push_back(l'\0');

which explicitly adds nul string when eventaully call temp.c_str() you'll double nul-terminated string need.


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