Re: [Freemint-discuss] Struct ucontext_t

[Thorsten O. <ad...@th...>]

On Donnerstag, 19. April 2018 10:10:33 CEST David Gálvez wrote:
> I've seen that sigmask is in a different position only in Linux-m68k
> kernel headers files, but in glibc and NetBSD
> is in the same location than in MiNTlib:

But the installed header file is machine dependent (it's a copy of  sysdeps/
unix/sysv/linux/{arch}/sys/ucontext.h from the source archive), and the one 
you are quoting there is not the one used for linux/m68k.

>My guess is that portable software is using glibc instead the Linux
>kernel headers file.

Well that structure isn't really portable. And IIRC correctly its not even 
defined in kernel headers.

Given that the functions aren't implement in Mintlib, and that the kernel does 
not pass the information to signal handlers, it is unlikely that any existing 
software for MiNT makes use of that structure. 

>Do you have in mind an example
>of a possible situation where having the registers
>in different positions in the struct would affect portability.

My goal would be to actually implement that functionality, both in the library 
and in the kernel. Actually i think it does not matter much how the structure 
is actually implemented, but it would make sense to use the same structure for 
both, so that the library does not have to make a copy of it. And for that it 
should be defined in a way that future enhancements are easier (e.g. more than 
32 signals numbers).

>"POSIX.1-2004 obsoleted these functions, and in POSIX.1-2008 they were
>removed, with POSIX Threads indicated as a possible replacement"

... the only problem being that there is no such thing as a posix-compliant 
thread library for mint, which is a  really stopper for a lot of modern 
applications. A lot of them don't even compile when pthread.h is not 
available.