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[Frama-c-discuss] Casting to a generic function pointer

Thanks, when I change the declaration from void *(void) to void *() I don't
get that error anymore.

I am not encountering an error saying --

[kernel:annot:missing-spec] src/os/unix/ngx_errno.c:67: Warning:

  Neither code nor specification for function strlen, generating default
assigns from the prototype

[value] src/os/unix/ngx_errno.c:67: builtin Frama_C_strlen: invalid base:
NULL


I had assumed that Frama-C automatically uses its own specfication for libc
functions such as strlen, so why do I get that complaint?

Thanks,
Divya

On Wed, Jul 4, 2018 at 7:55 AM, Virgile Prevosto <virgile.prevosto at m4x.org>
wrote:

> Hello,
>
>
> 2018-07-03 13:48 GMT+02:00 Divya Muthukumaran <divya84 at gmail.com>:
>
>>
>> I am trying to analyse nginx source code with Frama-C, and I want to run
>> Impact analysis on the preprocessed files. I ran into an issue where a
>> function declaration accepts a generic void (*) (void)
>> function pointer but the call to that function passes it something with a
>> different signature. Frama-c gives me this complaint.
>>
>> [kernel] src/event/ngx_event_openssl_stapling.c:185: Failure:
>>
>>   conversion between function types with different number of arguments:
>>
>>   int (*)(SSL *ssl_conn, void *data)
>>
>>   and
>>
>>   void (*)(void)
>>
>> Any ideas how how I can get past this?
>>
>>
> Indeed, Frama-C is now a bit restrictive on function pointer casts.
> Namely, if  both types provide a parameter type list, their length must be
> equal (so that analyzers can assume that at call site the actual function
> has the appropriate number of arguments). However, it is still possible to
> cast any function pointer to a function pointer that does not specify such
> a list, i.e. void(*)(). Note that you'll still get a warning about
> incompatible return types, but this is only a  warning and can be silenced
> with -kernel-warn-key="-typing:incompatible-types-call" option.
>
> Best regards,
> --
> E tutto per oggi, a la prossima volta
> Virgile
>
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>
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