Compiler does not detect Signal functions

Question

Good night!

I study computer engineering and have recently programmed in C due to a project... This same project uses two libraries (#include Signal.h, #include Signal.h). We use a server where all students program and use a program called Putty to connect to that server.

The problem arises when I use a program external to that server (e.g. Visual Studios, codeblock, codelite) and when I try to compile, it gives me the error of "implicit declariton of Function" from Kill function and yet, in relation to the signals, it says that the alarms are not declared (e.g. SIGKILL undeclared, first use in this Function).