char* namePtr = (char*) name.c_str(); You forgot () and that's why compiler treats c_str as function address instead of the address returned by the function.
On 1/25/07, Adriano Crestani <[EMAIL PROTECTED]> wrote:
OK, but when I try to do it: char* namePtr = (char*) name.c_str; I get this error message: Error 36 error C2440: 'type cast' : cannot convert from 'const char *(__thiscall std::basic_string<_Elem,_Traits,_Ax>::* )(void) const' to 'char *' I suppose that isn't allowed to cast from const to not const type. Adriano Crestani On 1/25/07, Pete Robbins <[EMAIL PROTECTED]> wrote: > > That is the "belt and braces" approach but if it's a perfomance issue it > would be OK to follow Yang's suggestion and jsut cast it to char*. Try it > and see if it works! > > On 25/01/07, Adriano Crestani <[EMAIL PROTECTED]> wrote: > > > > Thanks guys, you helped a lot. So I will copy the string to a char* and > > delete it after the usage. ; ) > > > > Adriano Crestani > > > > On 1/25/07, Pete Robbins <[EMAIL PROTECTED]> wrote: > > > > > > On 25/01/07, Yang ZHONG <[EMAIL PROTECTED]> wrote: > > > > > > > > Not every API is designed extremely careful: quite some times > "char*" > > > > doesn't mean the implementation may change the memory. > > > > I doubt SQLConnect change "char*", therefore you can safely cast > from > > > > "const > > > > char*" to "char*" > > > > > > > > > I agree. The API defines these as Input parameters so it SHOULD be > safe > > to > > > just cast the const char* to SQLCHAR* > > > > > > but... > > > > > > On 1/25/07, Adriano Crestani <[EMAIL PROTECTED]> wrote: > > > > > > > > > > It's an ODBC function: > > > > > > > > > > SQLConnect ( > > > > > SQLHDBC ConnectionHandle, /* hdbc */ > > > > > SQLCHAR *ServerName, /* szDSN > */ > > > > > SQLSMALLINT ServerNameLength, /* cbDSN > */ > > > > > SQLCHAR *UserName, /* szUID > */ > > > > > SQLSMALLINT UserNameLength, /* cbUID > */ > > > > > SQLCHAR *Authentication, /* > > szAuthStr > > > */ > > > > > SQLSMALLINT AuthenticationLength); > > > > > > > > > > > > > > > I'm needing to turn the server name that is a string object > > > > > into a char* to cast it to SQLCHAR* and I didn't find any other > > > > > function that takes const SQLCHAR* instead of SQLCHAR*. Thanks > again > > ; > > > ) > > > > > > > > > > > > > > > . > > > > > > > > > > > > > > > On 1/25/07, Pete Robbins <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > > OK. I have to ask.... what function are you calling that takes a > > > > char*? > > > > > Is > > > > > > there an equivalent that takes const char*? > > > > > > > > > > > > Cheers, > > > > > > > > > > > > > > > > > > On 25/01/07, Adriano Crestani <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > > > > I'm trying to use a function that requires a char* not const > as > > a > > > > > > > paremeter. > > > > > > > I think strdup will help a lot, thanks ; ) > > > > > > > > > > > > > > Adriano Crestani > > > > > > > > > > > > > > On 1/25/07, Pete Robbins <[EMAIL PROTECTED]> wrote: > > > > > > > > > > > > > > > > On 25/01/07, Adriano Crestani <[EMAIL PROTECTED]> > > wrote: > > > > > > > > > I'm begginer with C++ and I would like to know the best > way > > to > > > > > > obtain > > > > > > > a > > > > > > > > > char* from a string object, for example: > > > > > > > > > > > > > > > > > > string name = "Alice"; > > > > > > > > > char* namePtr = (char*) string; // this is not possible : > ( > > > > > > > > > > > > > > > > > > Obs.: I'm needing a char* and not a const char* pointer > > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > > > > > > > > Adriano Crestani > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > std::string has a .c_str() method to return the const char* > > > > > > > > const char* namePtr = name.c_str(); > > > > > > > > > > > > > > > > Why do you need char* and not const char*? You could cast > the > > > > value > > > > > to > > > > > > > > char* but it is const for a good reason... you should not > use > > c > > > > > > > > functions to manipulate the characters in std:string! > > > > > > > > > > > > > > > > You can take a copy of the string using strdup. > > > > > > > > > > > > > > > > Cheers, > > > > > > > > > > > > > > > > -- > > > > > > > > Pete > > > > > > > > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > > > > > > > > To unsubscribe, e-mail: > [EMAIL PROTECTED] > > > > > > > > For additional commands, e-mail: > > [EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Pete > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > > > Yang ZHONG > > > > > > > > > > > > > > > > > -- > > > Pete > > > > > > > > > > > > > -- > Pete > >
-- Yang ZHONG
