# Create log message on Numba compilation / Find out if given arguments lead to compilation

**URL:** <https://numba.discourse.group/t/create-log-message-on-numba-compilation-find-out-if-given-arguments-lead-to-compilation/114>\
**Category:** Development\
**Created:** [July 21, 2020, 9:57pm UTC](https://numba.discourse.group/t/create-log-message-on-numba-compilation-find-out-if-given-arguments-lead-to-compilation/114 "2020-07-21T21:57:58Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![Hannes](https://yyz2.discourse-cdn.com/free1/user_avatar/numba.discourse.group/hannes/32/188_2.png) [@Hannes](https://numba.discourse.group/u/Hannes)\
**Post date:** [July 22, 2020, 7:44am UTC](https://numba.discourse.group/t/create-log-message-on-numba-compilation-find-out-if-given-arguments-lead-to-compilation/114/3 "2020-07-22T07:44:30Z")

</div>

You could do some hackish monkey patching

```python
In [1]: import numba                                                                                                                                         

In [2]: oldcomp = numba.core.registry.CPUDispatcher.compile                                                                                                  

In [3]: def newcomp(*args, **kwargs): 
   ...: print("I am compiling") 
   ...: return oldcomp(*args, **kwargs) 
   ...:                                                                                                                                                      

In [4]: numba.core.registry.CPUDispatcher.compile = newcomp                                                                                                  

In [5]: @numba.njit 
   ...: def f(x): 
   ...: return x 
   ...:                                                                                                                                                      

In [6]: f(1)                                                                                                                                                 
I am compiling
Out[6]: 1

In [7]: f(1.0)                                                                                                                                               
I am compiling
Out[7]: 1.0

In [8]: f(1.0)                                                                                                                                               
Out[8]: 1.0

```

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_[View the full topic](https://numba.discourse.group/t/create-log-message-on-numba-compilation-find-out-if-given-arguments-lead-to-compilation/114)._