Passing unicode string

Question

2.00/5 (1 vote)

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Hye all,

How do I pass unicode sring parameter to my function? Was there any conversion needed?
So I have to pass the unicode string for example Run(L"Query")..
Then in my implementation code i define like this

void Run(wchar_t *message)
{
  DWORD cbRequest, cbWritten;
  cbRequest=sizeof(message);

  WriteFile(
        hPipe,                      // Handle of the pipe
        message,                  // Message to be written
        cbRequest,                  // Number of bytes to write
        &cbWritten,                 // Number of bytes written
        NULL                        // Not overlapped
      ));
}

but when i do debugging, the message writen was only one namely 'Q'..
How do i correct this?

Posted 2-Nov-10 21:12pm

Pdaus

Updated 3-Nov-10 0:24am

voloda2

v3

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5 solutions

Solution 5

hello,
After doing some trial and error, I found the solution but don't know this is acceptable or not..:~ unless it works. :rolleyes:

cbRequest= wcslen(message)*2
The concept:
wcslen(message) will calculate the lenght of string (1 for 1 char). Coz I was using the unicode, so multiply by 2, will produce wide character (16bit), so i can sent the exact bytes to be written... ;P

Keep looking for the proper solution... :doh:

Posted 3-Nov-10 1:54am

Pdaus

Updated 3-Nov-10 1:57am

v2

Comments

voloda2 3-Nov-10 8:04am

See my comment in Answer 3. Your solution is basically correct, but multiplication should be obtained using sizeof operator

ShilpiP 3-Nov-10 8:23am

Nops this is not the acceptable solution
Please try this cbRequest= (wcslen(message)+1)*sizeof(wchar_t *);

Emilio Garavaglia 6-Nov-10 16:59pm

Shilpi, that should be sizeof(wchar_t), not sizeof(wchar_t*).

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voloda2 · Accepted Answer · 2010-11-03T00:27:00

Solution 4

You must use wcslen() function to get string length in this case instead of sizeof.

cbRequest = wcslen(message);

Posted 3-Nov-10 0:27am

voloda2

Comments

Pdaus 3-Nov-10 7:18am

I only get "Que"..doesn't work

voloda2 3-Nov-10 7:48am

Sorry - you should have: cbRequest = wcslen(message) * sizeof(wchar_t) because unicode characters are stored as multiple bytes.

ShilpiP · Accepted Answer · 2010-11-02T23:25:00

Solution 3

Be specific...
What i understand is that your function takes ascii value as a argument and you want to pass unicode string ??
If so than use API WideCharToMultiByte.
cbRequest= (wcslen(message)+1)*sizeof(wchar_t *);

Posted 2-Nov-10 23:25pm

ShilpiP

Updated 3-Nov-10 0:57am

v2

Aescleal · Accepted Answer · 2010-11-02T22:23:00

Unicode characters are represented in C++ by the wchar_t character type. Unicode string literals are denoted by prefixing them with an L, because L is the first letter of Unicode, or wide, er, okay.

So when you want to declare a C style zero terminated string of unicode characters you use:

wchar_t *wide_text = L"I am wide text, feel my girth!";

and when you want to declare a function that takes this type of string you'd prototype it something like:

void display_message( const wchar_t *text_to_display );

However this being C++ why not use std::wstring for all your Unicode text needs?

Cheers,

Ash

PS: As Volodya said...

Your problem here is the sizeof - you telling it to use the size of a pointer and not the size of the character array you're passing into the function. You can use something like wcslen but had you used std::wstring instead the code would have been simpler.

voloda2 · Accepted Answer · 2010-11-02T21:14:00

Solution 1

Be more specific about the problem.

Basically you can use LPCWSTR type under Windows or std::wstring using STL.

Posted 2-Nov-10 21:14pm

voloda2

Updated 3-Nov-10 0:23am

v2

Passing unicode string

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