RFC: [PATCH] Make -static builds work again without crashing

Maarten Lankhorst m.b.lankhorst at gmail.com
Mon Apr 14 17:11:20 UTC 2008

Hello Denys,

 2008/4/14, Denys Vlasenko <vda.linux at googlemail.com>:

> On Monday 14 April 2008 05:06, Maarten Lankhorst wrote:
 >  > Hi all,
 >  >
 >  > After some experimenting I came to the conclusion that the minimum app
 >  > that won't crash with gcc -static is printf("%.0d", 0); which is
 >  > essentially a noop printf. So my patch calls that before calling main.
 >  >
 >  > Looking for feedback on the patch.
 > ?!
 >  Ths will force stdio to be linked it into every application.
 >  How about fixing the problem instead of papering over it?
 >  I think the possible reason is that _stdio_init is a weak symbol:
 >  extern void weak_function _stdio_init(void) attribute_hidden;
 >  and here we check that it was linked in, only if it was, we run it:
 >     /*
 >      * Initialize stdio here.  In the static library case, this will
 >      * be bypassed if not needed because of the weak alias above.
 >      * Thus we get a nice size savings because the stdio functions
 >      * won't be pulled into the final static binary unless used.
 >      */
 >     if (likely(_stdio_init != NULL))
 >         _stdio_init();
 >  But current gcc assumes (and it's allowed by C standard) that function
 >  address is never NULL. So it optimizes away this if(), and calls
 >  _stdio_init() unconditionally. If it indeed is NULL, we crash.

I don't think this is the issue here, if I remove the call to
 _stdio_init call in __uClibc_init it will still crash.



More information about the uClibc mailing list