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Re: serious compiler warnings in mingw64 build of master
From: |
Eli Zaretskii |
Subject: |
Re: serious compiler warnings in mingw64 build of master |
Date: |
Sat, 14 Aug 2021 20:42:00 +0300 |
> From: Stephen Leake <stephen_leake@stephe-leake.org>
> Date: Sat, 14 Aug 2021 10:18:56 -0700
>
> I just updated emacs/master (to
> bf55b5ac17cd5a40ad5ff2e25af7e050602180bb), and it's giving these
> compiler warnings:
>
> CC process.o
> In file included from process.c:33:
> process.c: In function 'Fmake_process':
> lisp.h:1561:31: warning: null pointer dereference [-Wnull-dereference]
> 1561 | return XSTRING (string)->u.s.data;
> | ~~~~~~~~~~~~~~~~~~~~~^~~~~
>
> This is from line 1990 in process.c:
> new_argv[i] = SSDATA (XCAR (tem));
>
> I have not tried to figure out a fix.
Neither did I.
> CC w32.o
> w32.c: In function '_sys_read_ahead':
> w32.c:8858:10: warning: 'rc' may be used uninitialized in this function
> [-Wmaybe-uninitialized]
> 8858 | if (rc == sizeof (char))
> | ~~~^~~~~~~~~~~~~~~~
>
> The preceding if/elsif block has no final 'else', so rc may not be set.
This is bogus: the compiler isn't smart enough to understand that the
3 possible flag bits are the only ones that can happen: a descriptor
is either for a pipe, or a serial connection, or a socket, because
_sys_read_ahead is only ever used for reading process output. I added
an initialization to pacify the compiler.
> I've been getting mysterious crashes when mail spawns a process to get
> more mail, so I'm hoping these are the root cause of that.
Unlikely, because this code hasn't changed in eons.