DevOps, CI/CD and Automation

if you look up munmap(2) it is defined as

#include <sys/mman.h>
int munmap(void *addr, size_t len);

But when used in CC it becomes

typedef char * caddr_t ;

#include <map>
extern int munmap ( caddr_t , size_t ) ;

Is there any standard describing this change? Why is that change?

Bye...Frank