How can read a unicode text file as character by character?

Le rner

CPallini wrote:

What kind of Unicode text file are you dealing with (e.g. UTF-8, etc..)?
What do you mean with 'character' (e.g. 'Unicode character' or 'single byte'?)?

Using Unicode encoding type file and one character means single byte.

CPallini

If you want to read a byte at time then use, as already suggested, fgetc[^]. :)

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[My articles]

Le rner

i m using this now but its not successful.

FILE *stream;
char buffer[2];
int kk, ch;

   // Open file to read line from:
   fopen\_s( &stream, OpenFile, "r" );
   if( stream == NULL )
   {
	   return ;
	  //exit( 0 );
   }

   // Read in first 80 characters and place them in "buffer": 
   ch = fgetc( stream );
   for( kk=0; (kk < 1 ) && ( feof( stream ) == 0 ); kk++ )
   {
	  buffer\[kk\] = (char)ch;
	  ch = fgetc( stream );
   }

   // Add null to end string 
   buffer\[kk\] = '\\0';
   printf( "%s\\n", buffer );
   fclose( stream );

here its unable to open the file and stream is alwaz null thats why its return.

Lost User

You are ignoring the return code from fopen_s so it's impossible to diagnose your problem. Use something like the following and look up the error code that you receive.

errno_t errNum = fopen_s( &stream, OpenFile, "r" );
if (errNum != 0)
{
// add some code here to display the error value
// or set a breakpoint and inspect its contents
}

I would suggest you look at the documentation here[^] for further guidance. Incidentally, the rest of your code does not seem to be set up to process Unicode data, which was the subject of your original question.

I must get a clever new signature for 2011.

Albert Holguin

Hope you do know that unicode is two bytes and ascii is one byte...

Emilio Garavaglia

UNICODE is actually a set of code-points whose cardinality requires 21 bits. When encoded in sequence of 1 bye is called UTF-8 and when encoded as sequence of two bytes is called UTF-16. In UTF-8 coding may vary from 1 to 4 bytes (and remains identical for code-points between 0 and 127, aka ASCII) In UTF-16 coding may be 2 or 4 bytes (and is TWO for the most of Latin, Cyrillic and Greek characters, as many simplified Chinese). UNICODE==2bytes is a misconception that originated at the time Windows included Unicode APIS using 16bits since -at that time- Unicode specs where not so wide. Actually, reading 2bytes does not necessarily means "read a character".

2 bugs found. > recompile ... 65534 bugs found. :doh:

Emilio Garavaglia

This is actually a miscoception ... see here[^].

2 bugs found. > recompile ... 65534 bugs found. :doh:

Albert Holguin

unfortunately, i think it depends on what standard of C/C++ and what OS. I'm pretty sure windows defines unicode as 16bits... from their website: "Unicode: A fixed-width, 16-bit worldwide character encoding that was developed and is maintained and promoted by the Unicode Consortium, a nonprofit computer industry organization." http://msdn.microsoft.com/en-us/library/cc194793.aspx[^]

Albert Holguin

Here's another reference to Microsoft: http://msdn.microsoft.com/en-us/library/2dax2h36.aspx[^]

Emilio Garavaglia

I'm sorry for you and for Microsoft, but the one and only entitled to say what Unicode was, is and will be is www.unicode.org[^] The page you linked is a very shame for Microsoft. A technical document like that cannot be written without specifying in the page itself a data when it was written (hey ... they speak about their new amazing Windows NT 3.5 ...) and for this sole fault should disqualify M$ of whatever authority in the field.

2 bugs found. > recompile ... 65534 bugs found. :doh:

Albert Holguin

so angry! :laugh: ...similar articles found in the MS VS2010 area of MSDN... i don't do much in unicode so haven't needed to worry about it...

Emilio Garavaglia

Nope. 1) Unicode is not a Microsoft product. What UNICODE is is defined by www.unicode.org[^] 2) Microsoft use to encode UNICODE into 16-bits units. That is a technique well defined by the UNICODE standard itself, known as UTF-16. Essentially, every code not in the range 0xD800-0xDFFF and lower than 0xFFFF is code as itself. Every other greater that 0xFFFF is broken in two 10-bits chunks, or-ed with 0xD800 and 0xDC00 respectively. The range 0xD800 - 0xDFFF is called "UNICODE surropgate" and does not contain valid codepoints. So you can have single unicode characters requiring two wchar_t in sequence to be represented and sequences of two wchar_t representing a single character, with code greater than 0xFFFF (typical for CJK - Chinese, Japanese, Corean characters).

2 bugs found. > recompile ... 65534 bugs found. :doh:

Albert Holguin

i certainly believe your point about unicode consortium being the authority... no argument there! :)

malaugh

If you have the program set to unicode, you need to use _wfopen_s to open the file, and the filename (OpenFile) needs to be specified as wchar_t something like wchar_t Myfile[] = "my_file.ext"; Then you should be able to use fgetwc to get the characters using ch = fgetwc( stream ); your should specify ch as wchar_t