# set\_trace\_func$B!(BNULL pointer given

**URL:** <https://www.ruby-forum.com/t/set-trace-func-b-bnull-pointer-given/111380>\
**Category:** Development\
**Created:** [August 6, 2007, 5:18pm UTC](https://www.ruby-forum.com/t/set-trace-func-b-bnull-pointer-given/111380 "2007-08-06T17:18:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![eklerni](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/b4bc9f/32.png) [@eklerni](https://www.ruby-forum.com/u/eklerni)\
**Post date:** [August 6, 2007, 5:18pm UTC](https://www.ruby-forum.com/t/set-trace-func-b-bnull-pointer-given/111380/1 "2007-08-06T17:18:33Z")

</div>

From:eklerni

1.9e$B$GHO0O1i;;;R$r;H$&$He(Bdebug.rbe$B$,%(%i!\<$K$J$j$^$9!#e(B

$ ruby -r debug -e ‘(1…3)’

#=\>  
Debug.rb  
Emacs support available.  
0: NULL pointer given (ArgumentError)

1.8.6e$B$G$OF1MM$N8=\>]$O$F8+$i$l$^$;$s$G$7$?!#e(B  
e$B860x$Oe(Bset\_trace\_funce$B$N$h$&$G!"0J2\<$N$h$&$K;H$C$b%(%i!\<$K$J$j$^$9!#e(B

–mylib.rb–  
set\_trace\_func lambda {|event, file, line, id, binding, klass|}

–do.rb–  
require ‘mylib’  
(1…3)

$ ruby ‘do.rb’  
#=\> 0: NULL pointer given (ArgumentError)

ruby 1.8.6 (2007-07-28 patchlevel 5000) [i386-mswin32\_80]  
ruby 1.9.0 (2007-08-01 patchlevel 0) [i386-mswin32\_80]