Merge pull request #99 from shinh/gets-again

Fix fgets implementation again
shinh · Feb 13, 2021 · 18b45bc · 18b45bc
2 parents c30d33f + a50477b
commit 18b45bc
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Showing 2 changed files with 26 additions and 8 deletions.
diff --git a/libc/stdio.h b/libc/stdio.h
@@ -207,8 +207,10 @@ char* fgets(char* s, int size, FILE* fp) {
   int i = 0;
   while (i < size - 1) {
     int c = fgetc(fp);
-    if (c == EOF)
-      break;
+    if (c == EOF) {
+      if (i) break;
+      return NULL;
+    }
     s[i++] = c;
     if (c == '\n')
       break;

diff --git a/test/fgets.c b/test/fgets.c
@@ -2,13 +2,29 @@
 
 int main() {
   char buf[256];
-  char* ptr = fgets(buf, 100, stdin);
-  printf("%d\n", ptr == buf);
-  printf("%s\n", ptr);
+  char* ptr;
+
   ptr = fgets(buf, 100, stdin);
-  printf("%d\n", ptr == buf);
-  printf("%s\n", ptr);
+  printf("%d %s\n", ptr == buf, ptr);
+
   ptr = fgets(buf, 100, stdin);
-  printf("%d\n", ptr == 0);
+  printf("%d %s\n", ptr == buf, ptr);
+
+  buf[0] = 'a';
+  ptr = fgets(buf, 100, stdin);
+  printf("%d %d\n", ptr == 0, buf[0]);
+
+  buf[0] = 'b';
+  ptr = fgets(buf, 1, stdin);
+  printf("%d %d\n", ptr == 0, buf[0]);
+
+  buf[0] = 'c';
+  ptr = fgets(buf, 100, stdin);
+  printf("%d %d\n", ptr == 0, buf[0]);
+
+  buf[0] = 'd';
+  ptr = fgets(buf, 0, stdin);
+  printf("%d %d\n", ptr == 0, buf[0]);
+
   return 0;
 }