Segmentation Fault - but no core dump ?

When I was working on a given binary - it gave me a "Segmentation Fault" but no core dump.

Started with the usual suspects .
* Checked the permission of the directory to see if the user has write permission to write the core file. It was ok.
* Checked the /tmp directory just in case.

Then I realized that I was working on bash, that sets core file size to be 0 automatically.

$ ulimit -a
core file size          (blocks, -c)   0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 20

..

Reset the same as below

$ ulimit -c unlimited

Now I ran my executable again and yes , this time the core dump is available for processing.