[fpc-pascal] Unicode chars losing information

[Florian Klämpfl]

> Am 09.03.2021 um 10:06 schrieb Michael Van Canneyt via fpc-pascal <fpc-pascal at lists.freepascal.org>:
> 
> 
> 
>> On Tue, 9 Mar 2021, Graeme Geldenhuys via fpc-pascal wrote:
>> 
>>> On 09/03/2021 1:44 am, Tomas Hajny via fpc-pascal wrote:
>>> UnicodeString may be used in a program simply because the included unit has it used in its interface. That may be the case even if there's no use of characters outside of US ASCII at all.
>> 
>> So FPC rather goes with the fact that data may be *silently* lost during
>> encoding conversions? That doesn't seem like a safe default behaviour to
>> me.
> 
> No, we give the programmer a choice: * Not use unicode conversion at all.
> * Use the C library to handle conversion (cwstring).
> * Use FPC native code to handle conversion (fpwidestring).
> * Some other means.
> 
> Since the compiler cannot reliably detect that a choice was made, it also cannot make the choice for you, because the choice also cannot be undone by the compiler.
> 
> This mechanism implies the programmer *has* to make that choice.
> 
> This is not different from the threading driver mechanism, for which Lazarus adds
> some {$IFDEF } mechanisms in the program uses clause.
> 
> But, I have been thinking about this. What we can do to alleviate this is the following:
> 
> Use the -FaNNN option of the command line.
> 
> This option will insert NNN implicitly in the uses clause of the program.
> 
> So, we can add -Fafpwidestring
> or
> -Facwstring
> 
> in the default generated fpc.cfg config file for selected platforms (mac, linux
> i386,64-bit, *bsd). The result will be that a widestring driver unit will be inserted by default for those platforms.
> 
> By using the necessary IFDEF mechanism in the config file, we can avoid
> inserting it for windows (which does not need it) or the smaller embedded platforms
> (which cannot handle it).
> 
> People that don't need/want this can remove the config setting from the file. All the others leave it as-is and will get their desired conversion mechanisms
> 'for free'.
> 
> This way a default choice is made for you on those platforms, but you can still 100% control
> it.

I am very much against this because this means that a default FPC executable would link against libc. And this is far too much only because a few people complain because they didn’t read the docs.

> 
> Michael.
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