Re: [Libevent-users] "test/regress_dns.c", line 618: error: void function cannot return value

[Dennis Clarke <dclarke@xxxxxxxxxxxxx>]

On 06/18/2018 10:21 PM, Azat Khuzhin wrote:
> > "test/regress_dns.c", line 618: error: void function cannot return value
>
> Hi,
>
> This is due to too strict compilers that does not allow ...

I see this all the time. Code that never get thrown into the blender of
strict compliance mode checks for portability reasons. A lot of code is
polluted with gnuism extensions to a point where finally folks started
talking about "gnu99" or "gnu11" as a made up bong smoke cloud language:

see https://gcc.gnu.org/onlinedocs/gcc-8.1.0/gcc/Standards.html#C-Language

    By default, GCC provides some extensions to the C language that, on
    rare occasions conflict with the C standard. ....

    Use of the -std options listed above disables these extensions where
    they conflict with the C standard version selected. You may also
    select an extended version of the C language explicitly with
    -std=gnu90 (for C90 with GNU extensions), -std=gnu99 (for C99 with
    GNU extensions) or -std=gnu11 (for C11 with GNU extensions).

So just hand waving made up stuff that laughs in the face of the specs.

Also the CFLAGS that I used were in the "loving and forgiving" mode
whereas strict to the harsh specifications would have been c99 with -Xc
compliance flags. However even the super friendly gcc 8.1.0 rejects the
use of a void function trying to return a value.  No lang spec flags :

$ /usr/local/gcc8/bin/gcc -m64 -c -o void_me.o void_me.c
void_me.c: In function 'no_ret_ever':
void_me.c:54:12: warning: 'return' with a value, in function returning void
     return fprintf ( stdout, "sum may be %i\n", foo + bar );
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
void_me.c:53:6: note: declared here
 void no_ret_ever( uint64_t foo, uint64_t bar ){
      ^~~~~~~~~~~
$

Where the void function being called was :

void no_ret_ever( uint64_t foo, uint64_t bar ){
    return fprintf ( stdout, "sum may be %i\n", foo + bar );
}

So wrong is wrong and I have no idea how any good compiler accepts that.

Dennis
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