1 #include <stdlib.h> 2 3 extern char **environ; 4 5 char * 6 getenv(const char *name) 7 { 8 char **p = environ; 9 char *v, *s1, *s2; 10 11 while (*p != NULL){ 12 for(s1 = (char *)name, s2 = *p++; *s1 == *s2; s1++, s2++) 13 continue; 14 if(*s1 == '\0' && *s2 == '=') 15 return s2+1; 16 } 17 return NULL ; 18 } 19