ref: 8f0db9f172617e54368422de1ee688eeae22941c dir: /sys/src/libc/port/abs.c/
#include <u.h> #include <libc.h> int abs(int a) { if(a < 0) return -a; return a; } long labs(long a) { if(a < 0) return -a; return a; }