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From: John Baldwin <jhb@FreeBSD.org>
To: Simon Marchi <simark@simark.ca>, Enze Li <enze.li@hotmail.com>,
	gdb-patches@sourceware.org
Cc: enze.li@gmx.com
Subject: Re: [PATCH] gdb: fix -Wdeprecated-declarations on macOS
Date: Tue, 28 Mar 2023 08:10:02 -0700	[thread overview]
Message-ID: <7657bb99-0319-ed79-fe2a-fb74a3876798@FreeBSD.org> (raw)
In-Reply-To: <6379554d-4e45-0ff8-a972-47596ea83b90@simark.ca>

On 3/28/23 7:55 AM, Simon Marchi via Gdb-patches wrote:
> On 3/28/23 10:16, Enze Li via Gdb-patches wrote:
>> I noticed that there are some issues when compiling on macOS.  There are
>> a few places where errors like the following are reported,
>>
>> ======
>>    CXX    cli/cli-cmds.o
>> cli/cli-cmds.c:929:14: error: 'vfork' is deprecated: Use posix_spawn or fork [-Werror,-Wdeprecated-declarations]
>>    if ((pid = vfork ()) == 0)
>>               ^
>> /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/unistd.h:604:1: note: 'vfork' has been explicitly marked deprecated here
>> __deprecated_msg("Use posix_spawn or fork")
>> ^
>> /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/sys/cdefs.h:208:48: note: expanded from macro '__deprecated_msg'
>>          #define __deprecated_msg(_msg) __attribute__((__deprecated__(_msg)))
>>                                                        ^
>> 1 error generated.
>> ======
>>
>> This patch is only available for the macOS platform.  This is done by
>> using macros to differentiate between specific platforms.
>>
>> Tested by rebuilding both on x86_64 linux and macOS Big Sur.
> 
> Any idea why vfork is deprecated on macOS?  I can't find any answer
> online.
> 
> I think it would be good to have a gdb_ util function with the ifdef at
> a single place, with an appropriate comment.  I don't know how to call
> this function though.  Would calling it gdb_vfork be misleading, because
> it won't always vfork?

Even if vfork is deprecated, you still want to use it instead of fork I think
as long as it exists.  The real fix is to add a patch to use posix_spawn
to fork the shell instead of vfork when posix_spawn exists.  posix_spawn is
just a wrapper around vfork + execve on FreeBSD's libc for example (I haven't
looked to see what it is on Linux but suspect it is similar).

-- 
John Baldwin


  reply	other threads:[~2023-03-28 15:10 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-28 14:16 Enze Li
2023-03-28 14:55 ` Simon Marchi
2023-03-28 15:10   ` John Baldwin [this message]
2023-03-28 15:57     ` Tom Tromey
2023-03-28 16:01     ` Simon Marchi
2023-03-28 17:52       ` John Baldwin
2023-03-28 17:57         ` John Baldwin

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