Char to LPCSTR

[hensa22]

hi all

how can convert of Char To LPCSTR,

well, I am developing a DLL to use it in VB and this is a function that I am building.

I try this, but it gives me bad result .

void LeerIni(LPCSTR *Valor, LPCSTR *Seccion, LPCSTR *Key, LPCSTR *FileIni
, long *nCant)
{
  char *res;
  GetPrivateProfileString(*Seccion, *Key,"-1", res, *nCant, *FileIni );
  *Valor=(LPCSTR )res; --here is the problem
}

DLL is created Ok.
but when this function is used in VB, *Valor return anything less value I hope

PDT. if anyone knows about develop DLL with C++ to user it in VB,
could help me out with some links I can use like guide.

[zdf]

Hello,

I don't know about VB. It looks like you know the same thing about C++.

There are too many mistakes in the code you posted. For instance:

char *res;
GetPrivateProfileString(*Seccion, *Key,"-1", res, *nCant, *FileIni );

When you declare a pointer to char it means you get exactly what you requested: a pointer to char; you do not get a pointer and space to store some characters. GetPrivateProfileString will try to store the result into the space pointed by res. But res points to a random location.

You must read a bit (more) about C++. Sorry...

[Mitsukai]

the function in your code does not allocate space for you..
why put this in a function ? they are axaclty the same

[hensa22]

Hello,

I don't know about VB. It looks like you know the same thing about C++.

There are too many mistakes in the code you posted. For instance:

char *res;
GetPrivateProfileString(*Seccion, *Key,"-1", res, *nCant, *FileIni );

When you declare a pointer to char it means you get exactly what you requested: a pointer to char; you do not get a pointer and space to store some characters. GetPrivateProfileString will try to store the result into the space pointed by res. But res points to a random location.

You must read a bit (more) about C++. Sorry...

thanks for reply, but I studied Borland c++ 3.0 before, but I have problem to develop DLL because I never have done it.

I understand that you mean me. I have to initialize 'res'.

[hensa22]

void LeerIni(LPCSTR *Valor, LPCSTR *Seccion, LPCSTR *Key, LPCSTR *FileIni
, long nCant)
{
  char *res;
  res=new char[nCant];
  GetPrivateProfileString(*Seccion, *Key,"-1", res, nCant, *FileIni );
  *Valor=(LPCSTR )res;
}

it's ok.
it works perfectly in VB

thanks.

[zdf]

Hello,

There are still errors in your code. For instance: LPCTSTR is a pointer to a vector of constant TCHAR. TCHAR is different from char, that is “*Valor=(LPCSTR )res;” is not all right.

Don’t forget to release the memory.

[Mitsukai]

LPCSTR is a pointer to memory which is used as an array of constant char's

the code is perfectly fine.is this C or C++

[zdf]

I am sorry but I do not understand. Why is it “perfectly fine”?

[hensa22]

void LeerIni(LPCSTR *Valor, LPCSTR *Seccion, LPCSTR *Key, LPCSTR *FileIni
, long nCant)
{
  char *res;
  res=new char[nCant];
  GetPrivateProfileString(*Seccion, *Key,"-1", res, nCant, *FileIni );
  *Valor=(LPCSTR )res;
}

this code above is still little bad.

long  LeerIni(LPSTR *Valor,const LPCSTR &Seccion, LPCSTR &Key, LPCSTR &FileIni,long &nCant)
{
  long c=-1;
  c=GetPrivateProfileString(Seccion, Key,"-1",*Valor,nCant,FileIni);  
  return c;
}

it's at 100% ok.it works in VB without problem.

[Mitsukai]

oh man i missed that mistake, i hate microsoft defines they are so hard to detect mistakes.

also why do make a temp var?
just make Valor = new char instead of a temp