c++ - I use CRegKey to open some, but this m_hKey != 0 -

i want jdk path registry, path is:

hkey_local_machine\\software\\javasoft\\java development kit\\1.8 

when use:

cregkey.open(hkey_local_machine, l"software\\javasoft\\java development kit\\1.8") 

it throws expression m_hkey != 0. what's happening ? how fix bug?

here code：

// java environment variable install path cregkey key; wchar_t javahome[40]; ulong szjavahome = 40; bool rest = key.open(hkey_local_machine, l"software\\javasoft\\java development kit\\1.8"); if (key.m_hkey == 0)     messagebox(l"11"); rest = key.querystringvalue(l"javahome", javahome, &szjavahome); 

you cannot use cregkey variable key after trying open it, without checking return value of it.

auto retopenkey = key.open(...); //long not bool if (error_success == retopenkey) {     //ok stuff key } else     auto err = getlasterror(); 

system error codes , / or formatmessage

you can in implementation of function, , debug in there, inline in header:

inline long cregkey::open(     _in_ hkey hkeyparent,     _in_opt_z_ lpctstr lpszkeyname,     _in_ regsam samdesired) throw() {     atlassume(hkeyparent != null);     hkey hkey = null;     long lres = m_ptm != null ?         m_ptm->regopenkeyex(hkeyparent, lpszkeyname, 0, samdesired, &hkey) :         regopenkeyex(hkeyparent, lpszkeyname, 0, samdesired, &hkey);     if (lres == error_success)     {         lres = close();         atlassert(lres == error_success);         m_hkey = hkey; #if winver >= 0x0501         m_samwow64 = samdesired & (key_wow64_32key | key_wow64_64key); #endif     }     return lres; }