I cant seem to understand and find the code under the functions cli() and sei(). I have found the source code of the interrupt library and i cant seem to find a "void cli() or void sei()". What part am I missing?
Look in wiring.h for sei().
sir can you please post the source code here?
Sorry, I was looking at the wrong one. I was looking at the Teensy definition. The AVR one appears to be in interrupt.h which in my installation is in C:\arduino-1.8.2\hardware\tools\avr\avr\include\avr\interrupt.h It defines it like this:
# define cli() __asm__ __volatile__ ("cli" ::: "memory")
Therefore cli() will ultimately be compiled as the single assembler instruction "cli".
Thank you :D