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From: Lars Erdmann <lars.erdmann@arcor.de>
Newsgroups: comp.os.os2.programmer.misc
Subject: Re: C: How to convert a \0 char into a dot for printf output?
Date: Fri, 18 May 2018 21:29:34 +0200
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On 18.05.18 19.34, Andreas Schnellbacher wrote:
> On 18.05.18 19:26, James Moe wrote:
>
>> On 05/18/2018 09:30 AM, Andreas Schnellbacher wrote:
>>
>>> I've tried to write a function that should convert each zero char into a
>>> dot. The following function doesn't work and I don't know why.
>>
>> It is because you are removing the string terminator.
>> You need to add a terminator to each string where you replace the
>> terminator so that downstream string processing works as expected.
>
> Thanks. I see, that makes sense. Sure, that's why in another function
> double-zero-terminated strings exist.
>
That's not really true. In C, if you define a string like

"String1\0String2\0"
then in fact, the C compiler will create a string that adds an 
additional zero terminator after this string. Just as it does for any 
string.
What you really need to do is check for the DOUBLE occurrence of a zero 
terminator in order to find the end of the string. Something like this 
(untested):

static PSZ _zerotodot( PSZ pszString)
{
          PSZ            p = pszString;

    if (p != NULL)
       {
       while ((*p != 0) || (*(p+1) != 0)) // !a || !b == !(a && b)
          {
          if (*p == 0)
             *p = '.';
          p++;
          }
          *p = '.';  // treat the very last "visible" zero terminator
       }

    return pszString; // you want to return the conv. string, don't you ?
}