Re: perhaps a dumb question re libsigsegv

[Dennis Clarke]

On 10/8/22 14:05, Bruno Haible wrote:
> [CCing the mailing list.]
>
> Dennis Clarke wrote:
> > Should libsigsegv be a C99 clean code base ? I have been looking at
> > libsigsegv back to 2.12 on FreeBSD amd64 and on Linux ppc64 and a few
> > other places and mmap() simply will not work with MAP_ANONYMOUS when I
> > ask for strict C99 or even C11.
.
.
.
> > So I guess the question is , gee, what is the C lang spec that I should
> > be using on all platforms for this ?
>
> First, you should be aware what relevant standards exist:
>    - C,
>    - POSIX: contains additional functions typically found on Unix-like systems,
>    - GNU: roughly the same as the LSB, contains additional functions provided
>      by the glibc. (And remember that glibc provides access to most Linux
>      kernel system calls.)
>
> The C standard can be chosen for a program that is written in portable C,
> for example a program that computes and prints N digits of pi.
>
> The POSIX standard can be chosen for a program that uses Unix features (e.g.
> mmap), for example a database program.
>
> The GNU "standard" should be chosen for a program that accesses all kinds
> of non-portable features.
>
> Second, the GCC manual [1] translates these choices into command-line options
> for GCC.
>
> Now, ask yourself: In which category is GNU libsigsegv? A library which makes
> use of a signal 'SIGSEGV', which exists in POSIX but not in C.
>
> Bruno
>
> [1] https://gcc.gnu.org/onlinedocs/gcc-12.2.0/gcc/C-Dialect-Options.html


Well that explains why I can do such things on the old Solaris systems
 but not on Linux. I have been edified !

--
Dennis Clarke
RISC-V/SPARC/PPC/ARM/CISC
UNIX and Linux spoken
GreyBeard and suspenders optional