On Mon, Dec 04, 2023 at 11:42:09AM +0100, Rainer Orth wrote:
> The recent warning patches broke the libssp build on Solaris:
>
> /vol/gcc/src/hg/master/local/libssp/gets-chk.c: In function '__gets_chk':
> /vol/gcc/src/hg/master/local/libssp/gets-chk.c:67:12: error: implicit
> declaration of function 'gets'; did you mean 'getw'?
> [-Wimplicit-function-declaration]
> 67 | return gets (s);
> | ^~~~
> | getw
> /vol/gcc/src/hg/master/local/libssp/gets-chk.c:67:12: error: returning 'int'
> from a function with return type 'char *' makes pointer from integer without
> a cast [-Wint-conversion]
> 67 | return gets (s);
> | ^~~~~~~~
> /vol/gcc/src/hg/master/local/libssp/gets-chk.c:74:12: error: returning 'int'
> from a function with return type 'char *' makes pointer from integer without
> a cast [-Wint-conversion]
> 74 | return gets (s);
> | ^~~~~~~~
>
> The guard around the gets declaration in gets-chk.c is
>
> #if !(!defined __USE_ISOC11 \
> || (defined __cplusplus && __cplusplus <= 201103L))
> extern char *gets (char *);
> #endif
>
> __USE_ISOC11 is a glibc-only thing, while Solaris <iso/stdio_iso.h>
> declares gets like
>
> #if __STDC_VERSION__ < 201112L && __cplusplus < 201402L
> extern char *gets(char *) __ATTR_DEPRECATED;
> #endif
>
> If one needs to check __USE_ISO11 at all, one certainly needs to check
> __STDC_VERSION__ to avoid breaking every non-glibc target. Besides, I
> don't see what's the use of checking __cplusplus when compiling a C-only
> source file. On top of all that, the double negation makes the guard
> unnecessarily hard to understand.
>
> I really don't know if it's useful/appropriate to check __USE_ISOC11 and
> __cplusplus here at all; still I've left both for now.
>
> Here's what I've used to complete the Solaris bootstrap.
>
> Tested on i386-pc-solaris2.11, sparc-sun-solaris2.11,
> x86_64-pc-linux-gnu, and x86_64-apple-darwin23.1.0.
>
> --
> -----------------------------------------------------------------------------
> Rainer Orth, Center for Biotechnology, Bielefeld University
>
>
> 2023-12-03 Rainer Orth <[email protected]>
>
> libssp:
> * gets-chk.c (gets): Avoid double negation.
> Also check __STDC_VERSION__ >= 201112L.
>
> # HG changeset patch
> # Parent 334015ab01f6c0e5af821c1e9bc83b8677cc0bfb
> libssp: Fix gets-chk.c compilation on Solaris
>
> diff --git a/libssp/gets-chk.c b/libssp/gets-chk.c
> --- a/libssp/gets-chk.c
> +++ b/libssp/gets-chk.c
> @@ -51,8 +51,9 @@ see the files COPYING3 and COPYING.RUNTI
> # include <string.h>
> #endif
>
> -#if !(!defined __USE_ISOC11 \
> - || (defined __cplusplus && __cplusplus <= 201103L))
> +#if (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L) \
> + || !defined __USE_ISOC11 \
> + || (defined __cplusplus && __cplusplus >= 201402L)
The above isn't equivalent. Avoiding double negation would mean
#if (defined __USE_ISOC11 \
&& !(defined __cplusplus && __cplusplus <= 201103L))
or
#if (defined __USE_ISOC11 \
&& (!defined __cplusplus || __cplusplus > 201103L))
No?
__USE_ISOC11 is defined as
/* This is to enable the ISO C11 extension. */
#if (defined _ISOC11_SOURCE || defined _ISOC2X_SOURCE \
|| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
# define __USE_ISOC11 1
#endif
where _ISOC11_SOURCE or _ISOC2X_SOURCE are defined whenever _GNU_SOURCE
is or when user defines them, or __USE_ISOC11 is also defined for
if __cplusplus >= 201703L.
Obviously, if you add that
(defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L)
it will mean it will be prototyped always (as I think we compile it without
any -std= flags).
What about using what we had for glibc (or even better, expect gets
to be declared for glibc < 2.16) and use what you add for other libraries?
The file is written and compiled as C, so we don't need to bother with C++
though.
So
#if (defined (__GLIBC_PREREQ) \
? (__GLIBC_PREREQ (2, 16) && defined (__USE_ISOC11)) \
: (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
?
> extern char *gets (char *);
> #endif
Jakub
