Cannot convert from 'const wchar_t *' to '_TCHAR *'

问题

_TCHAR* strGroupName = NULL;
const _TCHAR* strTempName = NULL;

//Assign some value to strTempName

strGroupName = _tcschr(strTempName, 92) //C2440

I get an error at the above line while compiling this code in VS2008. In VC6 it compiles fine.

Error C2440: '=' : cannot convert from 'const wchar_t *' to '_TCHAR *'

What seems to be the problem and how do I fix it?

回答1:

Try casting it as

strGroupName = (_TCHAR*)_tcschr(strTempName, 92);

Seems to me that VS2008 got a little more strict on type casts, and won't automatically do them in some cases.

回答2:

strGroupName = const_cast<_TCHAR*>( _tcschr(strTempName, 92));

This is because the variant of the function you're using has a const _TCHAR* as input and returns a const _TCHAR*.

Another variant would be to have strTempName declared as _TCHAR*, and not as const _TCHAR*. In this case, the variant function having a _TCHAR* parameter and returning a _TCHAR* value is used.

回答3:

strGroupName should also be a pointer to const.

const _TCHAR* strGroupName = _tcschr(strTempName, 92);

No need to declare it until the call to initialise it.

回答4:

_tcschr is returning a const pointer. Hence the return value should be const _TCHAR* strGroupName = NULL; If it is not possible to change strGroupName to a const pointer then declare both the pointers as non-const pointers.

来源：https://stackoverflow.com/questions/999727/cannot-convert-from-const-wchar-t-to-tchar