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From: Janis Papanagnou <janis_papanagnou+ng@hotmail.com>
Newsgroups: comp.lang.c
Subject: Re: Buffer contents well-defined after fgets() reaches EOF ?
Date: Sun, 16 Feb 2025 19:25:46 +0100
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On 16.02.2025 10:05, Michael S wrote:
> On Sun, 16 Feb 2025 07:32:23 -0000 (UTC)
> Kaz Kylheku <643-408-1753@kylheku.com> wrote:
> 
>> [...]
>> The strok function is ill-suited to many situations.  For instance,
>> there are situations in which you do want empty tokens, like CSV, such
>> that ",abc,def," shows four tokens, two of them empty.
>>
>> With the strspn and strcspn building blocks, you can easily whip up a
>> custom tokenizing loop that has the right semantics for the situation.
>>
>> We can also write our loop such that it restores the original
>> character that was overwritten in order to null-terminate the token,
>> simply by adding *end = more.  Thus when the loop ends, the string
>> is restored to its original state.
>>
>> I can understand code like that above without having to look up
>> anything, but if I see strtok or strtok_r code after many years of not
>> working with strtok, I will need a refresher on how exactly they
>> define a token.
> 
> For parsing of something important and relatively well-defined, like
> CSV, I'd very seriously consider option of not using standard str*
> utilities at all, with exception of those, where coding your own
> requires special expertise, i.e. primarily strtod(). BTW, even strtod()
> can't be blindly relied on for .csv, because it accepts hex floats,
> while standard CSV parser has to reject them.
> Most likely, avoiding fgets() is also a good idea in this case.

I certainly wouldn't call a CSV format as being "well-defined". But
CSV is certainly nasty enough to use some existing CSV library and
not re-invent the wheel in the first place.

Janis