ImportC openssl/ssl.h issues due to inttypes.h

[Witold Baryluk]

On Wednesday, 14 January 2026 at 10:44:32 UTC, Witold Baryluk 
wrote:
> gcc version 15.2.1 20251211 (Red Hat 15.2.1-5) (GCC)
>
> Fedora 42, amd64
>
> Just trying something for a test:
>
> ```
> $ gcc -E /usr/include/openssl/ssl.h > ssl.i
> /usr/include/openssl/ssl.h:19:10: warning: ‘#pragma once’ in 
> main file [-Wpragma-once-outside-header]
>    19 | # pragma once
>       |          ^~~~
>
> $ echo 'import ssl;' > foo.d
> $ gdc foo.d
> /usr/include/inttypes.h:358:51: error: found ‘__nptr’ when 
> expecting ‘,’
>   358 | extern intmax_t strtoimax (const char *__restrict 
> __nptr,
>       |                                                   ^
> /usr/include/inttypes.h:358:57: error: no type-specifier for 
> parameter
>   358 | extern intmax_t strtoimax (const char *__restrict 
> __nptr,
>       |                                                         
> ^
> /usr/include/inttypes.h:359:46: error: found ‘__endptr’ when 
> expecting ‘,’
>   359 |                            char **__restrict __endptr, 
> int __base) __THROW;
>       |                                              ^
> /usr/include/inttypes.h:359:54: error: no type-specifier for 
> parameter
>   359 |                            char **__restrict __endptr, 
> int __base) __THROW;
>       |                                                      ^
> /usr/include/inttypes.h:362:52: error: found ‘__nptr’ when 
> expecting ‘,’
>   362 | extern uintmax_t strtoumax (const char *__restrict 
> __nptr,
>       |                                                    ^
> /usr/include/inttypes.h:362:58: error: no type-specifier for 
> parameter
>
> ....
> ```
>
> Fail.
>
> Can we get some better documentation how to use for more than 
> some toy examples?

Note to myself: Issue is with no support for `__restrict`, this 
can be aliviated with defining it as a macro expanding to an 
empty string.

`gcc -E -D__restrict="" /usr/include/openssl/ssl.h > ssl.i`

for example.

Also passing `-P` does help, to make error messages somehow less 
confusing.

There are still some issues here and there unfortunately.

```
ssl.i:110:1: error: missing comma or semicolon after declaration 
of ‘__uint16_t’, found ‘__bswap_16’ instead
   110 | __bswap_16 (__uint16_t __bsx)
       | ^
ssl.i:113:1: error: no type for declarator before ‘}’
   113 | }
       | ^



...

ssl.i:119:31: error: missing comma or semicolon after declaration 
of ‘__inline’, found ‘__uint64_t’ instead
   119 | __extension__ static __inline __uint64_t

...


ssl.i:339:79: error: missing comma or semicolon after declaration 
of ‘strtoimax’, found ‘__asm__’ instead
   339 | extern intmax_t strtoimax (const char * __nptr, char ** 
__endptr, int __base) __asm__ ("" "__isoc23_strtoimax") 
__attribute__ ((__nothrow__ , __leaf__));
       |                                                           
                     ^


...

ssl.i:409:22: error: illegal combination of type specifiers
   409 | __extension__ extern long long int atoll (const char 
*__nptr)
       |                      ^
```

This is with

gcc (Debian 15.2.0-12) 15.2.0

and

gdc 15.2.0

on Debian testing, amd64


Some of these might be addressable with a bit more macro defines, 
but some like __asm__ stuff, might be tricky. These mostly do 
come from standard library, so there might be a way to address it 
somehow.