[Discuss-gnuradio] import error:undefined symbol

[Rahman, Muhammad Mahboob Ur]

Hi all,

I want to make a simple hard limiter block (hlimit_ff()) which works as follows:

if input<0
output=-1
else if input>0
output=1
else
output=0

So, in essence, I have downloaded the tar ball 
gr-how-to-write-a-block-3.2.tar.gz and replaced 'square' with 'hlimit' in the 
howto_square_ff.h, howto_square_ff.cc and modified the general work method (as 
above) in the howto_square_ff.cc and modified the makefile.am and howto.i in 
/src/lib appropriately. Also, I have modified the qa_howto.py in scr/python to 
run the test for hardlimit block. But I get the following error when I run make 
check:

Traceback (most recent call last):
  File "./qa_howto.py", line 24, in <module>
    import howto
  File "/home/mahboob/Desktop/howto/src/lib/howto.py", line 24, in <module>
    _howto = swig_import_helper()
  File "/home/mahboob/Desktop/howto/src/lib/howto.py", line 16, in 
swig_import_helper
    import _howto
ImportError: /home/mahboob/Desktop/howto/src/lib/.libs/_howto.so: undefined 
symbol: _Z23howto_make_hardlimit_ffv
FAIL: run_tests
==================
1 of 1 test failed
==================


Can any one please point out the mistake please?

Thanks,
Mahboob

p.s. I have checked and tried almost all options from the mailing list archive.