stdlib.h C functions not recognized by autocomplete

[gul]

Hello everyone,

I recently did a fresh install of my OS (Linux Mint 20), i installed codeblocks via default ubuntu repo (20.03-r11997), but when i tried to build default helloworld program i got an error "fatal error: stdio.h: No such file or directory".
So i found out i have to install build-essential package to fix that, now i can build but autocomplete still does not recognize any functions in stdlib.h (malloc calloc etc) its very frustrating any help would be very appreciated.

Thanks in advance.