handle printf("%s\n", 0)

b9432848 · rsc · 43baa1f2 · b9432848
--- a/printf.c
+++ b/printf.c
@@ -63,6 +63,8 @@ printf(int fd, char *fmt, ...)
      } else if(c == 's'){
        s = (char*)*ap;
        ap++;
+        if(s == 0)
+          s = "(null)";
        while(*s != 0){
          putc(fd, *s);
          s++;