Re: strlen man-page misinformation

[walter harms <wharms-fPG8STNUNVg@public.gmane.org>]

Am 18.02.2016 14:12, schrieb Michael Kerrisk (man-pages):
> Hello Alan,
> 
> On 02/03/2016 06:25 PM, Alan Aversa wrote:
>> Hello,
>>
>> The 2015-08-08 strlen man-page is incorrect. Here's a diff:
>>
>>     --- a/man3/strlen.3
>>     +++ b/man3/strlen.3
>>     @@ -45,7 +45,7 @@ excluding the terminating null byte (\(aq\\0\(aq).
>>      .SH RETURN VALUE
>>      The
>>      .BR strlen ()
>>     -function returns the number of bytes in the string
>>     +function returns the number of *characters* in the string that
>>     precede the terminating null character
> 
> I went for a simpler change: s/bytes/characters/


For my understanding this is wrong. 1 character may be represented by 2 or more bytes (utf8).
see this example, the string (test) is 3 characters long and takes 6 bytes space.

did i miss something ? did the specification of character change ?

re,
 wh

#include <stdio.h>
#include <string.h>

int main()
{
        char *test="ÖÄÜ";
        int i;
        int len=strlen(test);
        printf("strlen=%d\n",len);

        for(i=0;i<len;i++)
                printf("%02x\n",(unsigned char)*(test+i));

        return 0;
}



output:
strlen=6
c3
96
c3
84
c3
9c



> 
>>      .IR s .
>>      .SH ATTRIBUTES
>>      For an explanation of the terms used in this section, see
>>     @@ -60,7 +60,7 @@ T{
>>      T}     Thread safety   MT-Safe
>>      .TE
>>      .SH CONFORMING TO
>>     -POSIX.1-2001, POSIX.1-2008, C89, C99, SVr4, 4.3BSD.
>>     +POSIX.1-2001, POSIX.1-2008, C89, C99, C11, SVr4, 4.3BSD.
> 
> Fixed.
> 
>>      .SH SEE ALSO
>>      .BR string (3),
>>      .BR strnlen (3),
>>
>> Page 392 (PDF p. 390, §7.24.6.3) of the C11 standard
>> <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf> says:
>>
>>     The *strlen* function returns the number of characters that precede
>>     the terminating null character.
> 
> Thanks for the report. Interesting, POSIX.1 still uses the term "bytes"
> the spec.
> 
> Cheers,
> 
> Michael
> 
> 
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