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digitalmars.D.learn - setAssertHandler (druntime) segfaults

reply Lutger <lutger.blijdestijn gmail.com> writes:
There is a function setAssertHandler in druntime, but when I try to use it 
it segfaults. I'm not sure how it should be used, this is a complete example 
of what I try to do:

import std.stdio;
import core.exception;

void handleAssertion(string file, size_t line, string msg = null)
{
    writefln("assert in %s at line %s", file, line);
};

static this()
{
    setAssertHandler( &handleAssertion  );
}

unittest { assert(false); }

void main() {}


output:
assert in test at line 16
Segmentation fault

This is with dmd 2.031 on linux. Is this a bug, am I doing something wrong?
Jul 24 2009
next sibling parent reply Jarrett Billingsley <jarrett.billingsley gmail.com> writes:
On Fri, Jul 24, 2009 at 4:37 PM, Lutger<lutger.blijdestijn gmail.com> wrote=
:

 There is a function setAssertHandler in druntime, but when I try to use i=




 it segfaults. I'm not sure how it should be used, this is a complete exam=




 of what I try to do:

 import std.stdio;
 import core.exception;

 void handleAssertion(string file, size_t line, string msg =3D null)
 {
 =A0 =A0writefln("assert in %s at line %s", file, line);
 };

 static this()
 {
 =A0 =A0setAssertHandler( &handleAssertion =A0);
 }

 unittest { assert(false); }

 void main() {}


 output:
 assert in test at line 16
 Segmentation fault

 This is with dmd 2.031 on linux. Is this a bug, am I doing something wron=




Hm, it might - and I'm just taking a wild guess here - be that
std.stdio hasn't yet been initialized when you do the writefln in your
assertion handler.  But you really should try using a debugger to get
a stacktrace.
Jul 24 2009
parent reply Lutger <lutger.blijdestijn gmail.com> writes:
Jarrett Billingsley wrote:


 On Fri, Jul 24, 2009 at 4:37 PM, Lutger<lutger.blijdestijn gmail.com>
 wrote:

 There is a function setAssertHandler in druntime, but when I try to use
 it it segfaults. I'm not sure how it should be used, this is a complete
 example of what I try to do:

 import std.stdio;
 import core.exception;

 void handleAssertion(string file, size_t line, string msg = null)
 {
 writefln("assert in %s at line %s", file, line);
 };

 static this()
 {
 setAssertHandler( &handleAssertion  );
 }

 unittest { assert(false); }

 void main() {}


 output:
 assert in test at line 16
 Segmentation fault

 This is with dmd 2.031 on linux. Is this a bug, am I doing something
 wrong?



 Hm, it might - and I'm just taking a wild guess here - be that
 std.stdio hasn't yet been initialized when you do the writefln in your
 assertion handler.  But you really should try using a debugger to get
 a stacktrace.



Ok I tried. Funny thing, with -g enabled it doesn't segfault anymore. 
Without -g, the trace is not intelligible to me. Segfault also occurs when 
commenting out writefln.

This is useless I assume but anyway, this is what gdb gives me:

#0  0x0805292e in _TMP257 ()
#1  0x0000000e in ?? ()
#2  0xffffd02c in ?? ()
#3  0x08048f79 in _D4test11__unittest1FZv ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
Jul 24 2009
parent Lutger <lutger.blijdestijn gmail.com> writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208
Jul 24 2009
prev sibling parent Jarrett Billingsley <jarrett.billingsley gmail.com> writes:
On Fri, Jul 24, 2009 at 5:46 PM, Lutger<lutger.blijdestijn gmail.com> wrote=
:

 Jarrett Billingsley wrote:


 On Fri, Jul 24, 2009 at 4:37 PM, Lutger<lutger.blijdestijn gmail.com>
 wrote:

 There is a function setAssertHandler in druntime, but when I try to use
 it it segfaults. I'm not sure how it should be used, this is a complete
 example of what I try to do:

 import std.stdio;
 import core.exception;

 void handleAssertion(string file, size_t line, string msg =3D null)
 {
 writefln("assert in %s at line %s", file, line);
 };

 static this()
 {
 setAssertHandler( &handleAssertion =A0);
 }

 unittest { assert(false); }

 void main() {}


 output:
 assert in test at line 16
 Segmentation fault

 This is with dmd 2.031 on linux. Is this a bug, am I doing something
 wrong?



 Hm, it might - and I'm just taking a wild guess here - be that
 std.stdio hasn't yet been initialized when you do the writefln in your
 assertion handler. =A0But you really should try using a debugger to get
 a stacktrace.



 Ok I tried. Funny thing, with -g enabled it doesn't segfault anymore.
 Without -g, the trace is not intelligible to me. Segfault also occurs whe=




 commenting out writefln.

 This is useless I assume but anyway, this is what gdb gives me:

 #0 =A00x0805292e in _TMP257 ()
 #1 =A00x0000000e in ?? ()
 #2 =A00xffffd02c in ?? ()
 #3 =A00x08048f79 in _D4test11__unittest1FZv ()
 Backtrace stopped: previous frame inner to this frame (corrupt stack?)



I'm.. utterly at a loss.  It seems that exiting the assertion handler
by doing anything other than throwing an exception causes the
segfault.  And like you said, -g makes the problem disappear.  I have
no idea what's going on.
Jul 24 2009