asked on

cast to int + return a LPSIZE

There are 2 errors in the following function. I am attempting to cast Text.length to an integer - how? Also I want to correctly return a LPSIZE - how?

LPSIZE CNodeView1::TextExt(HDC dc, string Text)
{
LPSIZE res;
GetTextExtentPoint32(dc, Text.c_str(), (integer) Text.length, res);
return res;
}

Note that this is the official definition of the GetTextExtentPoint32 function:

BOOL GetTextExtentPoint32(
HDC hdc, // handle to device context
LPCTSTR lpString, // pointer to text string
int cbString, // number of characters in string
LPSIZE lpSize // pointer to structure for string size
);

Finally - should I be passing in char * to make my life easier?

thanks

Wyn

Try:

LPSIZE CNodeView1::TextExt(HDC dc, string Text)
{
SIZE res;
GetTextExtentPoint32(dc, Text.c_str(),Text.length, &res);
return &res;
}

wylliker

First, casting the length should be - (int)

Second, your variable - res - needs to be defined as:

SIZE res;

Your function call becomes ...

GetTextExtentPoint32(dc, Text.c_str(), (int) Text.length, &res);

Give this a try.

Wyn

or

SIZE size;
LPSIZE res;

LPSIZE CNodeView1::TextExt(HDC dc, string Text)
{
GetTextExtentPoint32(dc, Text.c_str (),Text.length, &size);
return &res;
}

Wyn

Ignore last comment,I miswrite.
I mean:

private:
SIZE size;
LPSIZE res;
.............

LPSIZE CNodeView1::TextExt(HDC dc, string Text)
{
GetTextExtentPoint32(dc, Text.c_str (),Text.length, &size);
return &size;
}

...............

res=TextExt(...);

abulka

ASKER

Oh yeah - I want to use the above function like this:

long LineHeight = TextExt(mydc, "Aj").cy;

ASKER CERTIFIED SOLUTION

alexo

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abulka

ASKER

Wyn - looks like I actually don't need to declare
LPSIZE res;
since the function is not using it?

Also, when I typed in
LPSIZE CNodeView1::TextExt(HDC dc, string Text)
{
GetTextExtentPoint32(dc, Text.c_str(), (int) Text.length, &size);
return &size;
}

and compiled it I found that I had to includ an integer cast - cos I got a compile error. Even so, I am still getting an error re that attempted cast!!

CNodeView1.cpp(553) : error C2440: 'type cast' : cannot convert from 'unsigned int (__thiscall std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >::*' to 'int'
Conversion is a valid standard conversion, which can be performed implicitly or by use of static_cast, C-style cast or function-style cast

abulka

ASKER

alexo - your code also fails on the line with the integer cast thus:
D:\My Documents\aa Vc\ts1\CNodeView1.cpp(561) : error C2065: 'integer' : undeclared identifier
D:\My Documents\aa Vc\ts1\CNodeView1.cpp(561) : error C2146: syntax error : missing ')' before identifier 'Text'
D:\My Documents\aa Vc\ts1\CNodeView1.cpp(561) : error C2059: syntax error : ')'

Wyn

->Wyn, don't EVER return an address of an automatic (local on the stack) variable!
==================================
Yes,I mean res and I rewrite one later just for this. But you'v got to admit at the very point the function returns,the value is still there on stack,although become tragedy later.

wylliker

Yeah, we all missed on the (int) cast

should be (int) Text.length()

Wyn

wylliker,I think in your first comment You already have the code,(int)Text.length().You dont miss it:)

Wyn

->looks like I actually don't need to declare
LPSIZE res;
since the function is not using it?
=================
Doesnt matter,just sample.

wylliker

Wyn,

No, I did miss the () after length. As it is a member function - every example had incorrectly ...

(int) Text.length

instead of

(int) Text.length()

I also forgot about the return value being a pointer to a SIZE structure.

Wyn

O,:)
I even dont realize the () after the length until I read your last comment:-)

I concentrate myself to other parts of code.:0

Yes,it's a function:)

Sorry,wylliker .....:)

LucHoltkamp

Why return a LPSIZE??????
It's more logical to return a SIZE! If you return a pointer, you need a variable to hold the value, as a member in you're class or as a static...
Not neccesairy, the way to go is returning a SIZE

SIZE CNodeView1::TextExt(HDC dc, string Text)
{
SIZE res;
GetTextExtentPoint32(dc, Text.c_str(),Text.length, &res);
return res;
}

Wyn

yup ,it's also my first way to go...The second I use &res.

abulka

ASKER

abulka

ASKER

Seems that

SIZE CNodeView1::TextExt(HDC dc, string Text)
{
SIZE res;
GetTextExtentPoint32(dc, Text.c_str(), (int) Text.length(), &res);
return res;
}

compiles correctly. I assume the
return res
is not returning the actual local variable (which will disappear off the call stack as soon as the function exits), but a copy of res. I hope so :-)

abulka

ASKER

alexo

abulka, the (integer) cast was in the original code so I assumed it was correct (maybe a typedef to int?). It should really be (int).

Returning a local variable is no problem since you return BY VALUE. Tha is - a copy of the local variable. On the other hand, returning a POINTER to a local variable (or a REFERENCE) to it usually makes your program go BOOM!

abulka

ASKER

alexo seems to be the first one to get the closest to the answer. And of course, the correct typecast is (int) rather than (integer)

SIZE CNodeView1::TextExt(HDC dc, string Text)
{
  SIZE res;
  GetTextExtentPoint32(dc, Text.c_str(), (int) Text.length(), &res);
  return res;
}