[Solved] Re: Is importC ready?

[bachmeier]

On Monday, 15 November 2021 at 21:29:53 UTC, bachmeier wrote:
> On Tuesday, 9 November 2021 at 16:41:04 UTC, bachmeier wrote:
>> I tried to compile a simple C file this morning, containing
>>
>> ```
>> #include "nmath.h"
>>
>> double fsign(double x, double y)
>> {
>> #ifdef IEEE_754
>>     if (ISNAN(x) || ISNAN(y))
>> 	return x + y;
>> #endif
>>     return ((y >= 0) ? fabs(x) : -fabs(x));
>> }
>> ```
>>
>> I assumed this would be straightforward since it doesn't have 
>> a bunch of dependencies and it's only a few lines of code. 
>> Instead, I got a stream of errors. After running the file 
>> through the preprocessor, I had to comment out anything with
>>
>> -  `__extension__`
>> - Restricted pointers `*__restrict`
>> - `_Float128`
>> - `__asm__`
>>
>> And in the source, anything with ISNAN, or in the preprocessed 
>> file,
>>
>> - `__builtin_isnan`
>>
>> I [filed a 
>> bug](https://issues.dlang.org/show_bug.cgi?id=22496). After 
>> this experience, it's not obvious to me that importC is ready 
>> to be part of a stable compiler release. Maybe I just had bad 
>> luck with the choice of file.
>
> There's a solution for this. Buried in a recent post on This 
> Week in D, there's [a link to a list of 
> fixes](https://raw.githubusercontent.com/ibuclaw/importC/main/src/keywords.c.in). That plus `#define __builtin_isnan isnan` allows my C file and many others to compile with LDC. Some files that compile with LDC do not compile with DMD. I'm still having trouble with `__builtin_isfinite` errors. I thought `#define __builtin_isfinite isfinite` would work, but it doesn't.
>
> Once I understand this better, I will update the issue I 
> created.

Giving up on this experiment. It's much easier/faster to wrap 
what I need and forget about the rest. Solve one problem and you 
get three new compiler error messages. Eventually I run into 
something I can't fix, so I move on to a new file, and it's the 
same thing. It's hopeless without a complete implementation or 
workaround for all of the GCC compiler extensions. I honestly 
have no idea why they pretend C is standardized.