1 /* 2 * strerror.c 3 */ 4 5 #include <string.h> 6 strerror(int errnum)7char *strerror(int errnum) 8 { 9 static char message[32] = "error "; /* enough for error 2^63-1 */ 10 char numbuf[32]; 11 char *p; 12 unsigned int e = (unsigned int)errnum; 13 14 extern const int sys_nerr; 15 extern const char *const sys_errlist[]; 16 17 if (e < (unsigned int)sys_nerr && sys_errlist[e]) 18 return (char *)sys_errlist[e]; 19 20 p = numbuf + sizeof numbuf; 21 *--p = '\0'; 22 23 do { 24 *--p = (e % 10) + '0'; 25 e /= 10; 26 } while (e); 27 28 memcpy(message + 6, p, (numbuf + sizeof numbuf) - p); 29 30 return message; 31 } 32