Std::string loadstring???

[Aescleal]

Cool, I'd either forgotten about or never known the behaviour of LoadString when you pass zero as the buffer size. What's the reason this wouldn't work on ANSI as well?

[Stephen Hewitt]

I'm not positive, but it doesn't seem to. Note that the documentation says it returns a pointer to the raw resource and string resources are always Unicode, so perhaps this is a reason. In fact, in the ANSI case 0xFFFFffff was returned to indicate an error (when 0 is passed as the buffer size), which isn't mentioned in the documentation.

Steve

[Lost User]

Hi, Not sure who gave me a one vote... but the solution I presented is a secure and safe method for loading a std::string from a resource. The method presented by Aescleal will fail for a string greater than the 4096 constant. The wstring solution presented by Stephen Hewitt just flat out doesn't work for std::string Best Wishes, -David Delaune

[Stephen Hewitt]

It does for a wstring (which was all it was intended to, it wasn't a reply to the OP but to Aescleal). It's documented. MSDN (on LoadString):

nBufferMax [in] int The size of the buffer, in characters. The string is truncated and null-terminated if it is longer than the number of characters specified. If this parameter is 0, then lpBuffer receives a read-only pointer to the resource itself.

Secondly, I tried it (after reading the documentation thoroughly first) and verified that it did work. Finally, your technique will not work. LoadResource returns nothing that LoadString can consume.

Steve

[Aescleal]

Thanks for that, I'll stick that on the list as the first new thing I've learnt today. Ash

[Aescleal]

I didn't give you a 1 vote but the method I outlined will work for strings greater than 4096 characters, it just won't load the whole string. If you're really worried about that you have to use the OS/2 vintage "try it once to fail, once to succeed" method of sizing buffers. And it'd be fairly easy to change Stephen's method to work for std::string - depending on how much you know about the resource and the characters in it it's either trivial (use the two iterator string constructor) or slightly harder (use wcstombs). Ash

[Lost User]

Stephen Hewitt wrote:

Finally, your technique will not work. LoadResource returns nothing that LoadString can consume.

Hi Stephen, You may be correct. I was thinking that you could just do something like this:

HRSRC hres = FindResource(NULL, MAKEINTRESOURCE(IDS_SOMESTRING), RT_STRING);
DWORD dwSizeRes = SizeofResource(NULL,hres);
char *p = NULL;
int result = LoadString((HINSTANCE)&__ImageBase,AFX_IDS_APP_TITLE,p,0);
std::string s(p,dwSizeRes);

Which is not much different than what you posted. With the method that you posted...I am thinking that the std::string would need a NULL terminator in the string resource. I admit that I have not tried either method (including the one I just typed above). I will test both methods later when I get some free time. Best Wishes, -David Delaune

[Lost User]

Hey Steve :) I just spent 30 minutes testing both of our code samples. I could not get the code you wrote working for std::string probably because the resource strings are actually stored in Unicode within the PE files. However for wstrings your code is absolutely perfect. I suspect... that the brilliant code you posted could be actually be modified to utilize wcstombs and work for both ANSI and Unicode builds. As for my code sample... I had even less success although I was eventually able to get it working. I had to re-read some of the MSDN docs and ended up using FindResourceEx with the language identifier. To make things worse the address I was recieving was the start of the string resource block. I had to load the string block into an HGLOBAL and walk the string table before I could even read the string. :doh: Anyway I just wanted to let you know that you were correct. :) Best Wishes, -David Delaune

[Alain Rist]

See my answer including Stephen Hewitt contribution at http://www.codeproject.com/Tips/86496/Load-a-Windows-string-resource-into-a-std-string-o.aspx[^] cheers, AR

When the wise (person) points at the moon the fool looks at the finger (Chinese proverb)

[Stephen Hewitt]

Thanks.

Steve

[gmallax]

Very nice and useful..Thanx :)

[Alain Rist]

gmallax wrote:

Very nice and useful

Then please upvote. Thanks, AR

When the wise (person) points at the moon the fool looks at the finger (Chinese proverb)

[gmallax]

hi, here we declare char buffer as char buffer[ 1024 ] = { '\0' }.. How to release this?

[Alain Rist]

It is released at the next }

ReturnType SomeClass::SomeFunction(SomeParams)
{
char buffer[1024] = {0}; // this a stack allocation
// any code ...
return ReturnType::SomeValue;
} // buffer is deallocated here

cheers, AR

When the wise (person) points at the moon the fool looks at the finger (Chinese proverb)