sprintf for utf8 formated characters

[Mandragon03]

Anyone know if the standard sprintf supports utf8 characters that
extend beyond the normal ascii characters?

Thanks!

[Michal Nazarewicz]

Ma*********@gma il.com writes:

Anyone know if the standard sprintf supports utf8 characters that
extend beyond the normal ascii characters?

That depends on what you mean by "support". If you do thing like:

sprintf(buf, "%s", some_string);

(but never do that unless you are sure buf has enough space) or
something along the lines of:

sprintf(buf, format, arg1, arg2 /* ... */);

(of course be sure format is valid and buf has enough space) and all
strings are UTF-8 encoded you'll get UTF-8 encoded string in the end.
This is guaranteed because UTF-8 is designed in such a way that NUL
bytes never occur in sequences encoding other characters.

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
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[Mandragon03]

On Apr 14, 2:39 pm, Michal Nazarewicz <[e-mail] wrote:

Mandrago...@gma il.com writes:

Anyone know if the standard sprintf supports utf8 characters that
extend beyond the normal ascii characters?

That depends on what you mean by "support". If you do thing like:

sprintf(buf, "%s", some_string);

(but never do that unless you are sure buf has enough space) or
something along the lines of:

sprintf(buf, format, arg1, arg2 /* ... */);

(of course be sure format is valid and buf has enough space) and all
strings are UTF-8 encoded you'll get UTF-8 encoded string in the end.
This is guaranteed because UTF-8 is designed in such a way that NUL
bytes never occur in sequences encoding other characters.

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +--<mina86*tlen.pl >--<jid:mina86*jab ber.org>--ooO--(_)--Ooo--

Thanks for the reply.

What is still left unanswered is whether I can put utf-8 strings (ie
they have characters that take up to 4 bytes of space) and sprint f
that into a string without screwing up the byts of data. So something
like this:

unsigned int myVar= 0xDB0;

convertMyVarToU TF8(myVar);

char buff[512];

sprintf( buff, "Long string with %u", myVar);

is there a legitimate UTF-8 string in buff at this point?

Thanks!

Mandragon

[James Kanze]

On 15 avr, 23:02, Mandrago...@gma il.com wrote:

On Apr 14, 2:39 pm, Michal Nazarewicz <[e-mail] wrote:

[...]

What is still left unanswered is whether I can put utf-8 strings (ie
they have characters that take up to 4 bytes of space) and sprint f
that into a string without screwing up the byts of data. So something
like this:

unsigned int myVar= 0xDB0;

convertMyVarToU TF8(myVar);

char buff[512];

sprintf( buff, "Long string with %u", myVar);

is there a legitimate UTF-8 string in buff at this point?

If the native encoding of narrow character strings is ASCII, or
an encoding which uses ASCII for its lower 128 code points, yes.
Because "%u" will only generated characters in the range
[0-9a-f], and all of those characters have the same encoding in
ASCII and in UTF-8.

However, I suspect that the function convertMyVarToU TF8 is
supposed to do something. But I don't see what, and I don't see
what it could do which would affect the results here.

--
James Kanze (GABI Software) email:ja******* **@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[Michal Nazarewicz]

Ma*********@gma il.com writes:

What is still left unanswered is whether I can put utf-8 strings (ie
they have characters that take up to 4 bytes of space) and sprint f
that into a string without screwing up the byts of data. So something
like this:

unsigned int myVar= 0xDB0;
convertMyVarToU TF8(myVar);
char buff[512];
sprintf( buff, "Long string with %u", myVar);

is there a legitimate UTF-8 string in buff at this point?

Are you sure you meant that code? I suspect you meant something like:

#v+
char *utf8char(unsig ned long code);
char buf[512];
sprintf(buf, "Long string with %s", utf8char(0xDB0) );
#v-

Where "utf8char" converts given code to it's UTF-8 representation and
follows it by NUL byte returning pointer to first byte of the sequence.
If CHAR_BIT==8 and strings literals use ASCII codes for all alphanumeric
characters then in the end buf will contain a valid UTF-8 encoded
string.

Basically, if your implementation doesn't do anything funky with string
literals you can use UTF-8 encoded strings almost like any other
strings. The thing you'll have to remember is that some characters take
up more then one byte so ie. strlen() won't return string length, and
foo[10] won't necessarily get you the 11th character.

--
Best regards, _ _
.o. | Liege of Serenly Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michal "mina86" Nazarewicz (o o)
ooo +--<mina86*tlen.pl >--<jid:mina86*jab ber.org>--ooO--(_)--Ooo--