Date: Wed, 22 Jun 2016 23:04:18 -0700 From: weimingz@...eaurora.org To: musl@...ts.openwall.com Cc: Rich Felker <dalias@...ifal.cx>, Rich Felker <dalias@...c.org> Subject: Re: build musl for armv7m If it is not a weak symbol, you may get "multi-def" error. It depends on the obj/lib order on command line. If it is a weak symbol, then a non-weak symbol can override it. Anyway, your comment reminds me that we can use -wrap=exit to override it. So no change is needed. btw, will you commit the change of those .s files for armv7m ? Thanks, Weiming On 2016-06-22 21:22, Rich Felker wrote: > On Wed, Jun 22, 2016 at 05:21:54PM -0700, Zhao, Weiming wrote: >> Fixed. >> >> Btw, can we make exit() weak function? (patch attached) >> >> This allows user code to redefine it because in baremetal >> environment, sometime we want to customize it. For example, some >> code never exits, so we can define a dummy exit() and thus save code >> size. > > No, this is a hack and is not even needed to do what you're asking > for. The way linking an archive works, an object in the archive is > only pulled in to the link process when it satisfies an undefined > symbol reference, and if you defined your own exit, then exit.o would > never have reason to get linked. > > But there are all sorts of things that can break unexpectedly from > redefining standard functions, which is why it's UB and this is not > supported usage. > > Rich
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