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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Whaddaya think?
Date: Sat, 15 Jun 2024 22:21:59 -0700
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Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:
> On 16.06.2024 05:41, Janis Papanagnou wrote:
>> On 16.06.2024 05:26, Lawrence D'Oliveiro wrote:
>>> On Sun, 16 Jun 2024 01:56:49 +0300, Michael S wrote:
>>>
>>>> If you want to preserve you sanity, never use fscanf().
>>>
>>> Quoth the man page <https://manpages.debian.org/3/scanf.3.en.html>:
>>>
>>>     It is very difficult to use these functions correctly, and it is
>>>     preferable to read entire lines with fgets(3) or getline(3) and
>>>     parse them later with sscanf(3) or more specialized functions such
>>>     as strtol(3).
>> 
>> This would be also my first impulse, but you'd have to know
>> _in advance_ how long the data stream would be; the function
>> requires an existing buffer. So you'd anyway need a stepwise
>> input. [...]
>
> Would it be sensible to have a malloc()'ed buffer used for the first
> fgets() and then subsequent fgets() work on the realloc()'ed part? I
> suppose the previously set data in the malloc area would be retained
> so that there's no re-composition of cut numbers necessary?

Sure.  "The contents of the new object shall be the same as that of the
old object prior to deallocation, up to the lesser of the new and old
sizes."

Keep in mind that you can't call realloc() on a non-null pointer that
wasn't allocated by an allocation function.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */