Make ungetc(EOF) a no-op.

dlls/msvcrt/file.c

@@ -2190,7 +2190,7 @@ char *MSVCRT_fgets(char *s, int size, MSVCRT_FILE* file)
   if ((cc != MSVCRT_EOF) && (size > 1))
     *s++ = cc;
   *s = '\0';
-  TRACE(":got '%s'\n", debugstr_a(buf_start));
+  TRACE(":got %s\n", debugstr_a(buf_start));
   return buf_start;
 }
 
@@ -2983,6 +2983,8 @@ int MSVCRT_printf(const char *format, ...)
  */
 int MSVCRT_ungetc(int c, MSVCRT_FILE * file)
 {
+	if (c == MSVCRT_EOF)
+		return MSVCRT_EOF;
 	if(file->_bufsiz == 0 && !(file->_flag & MSVCRT__IONBF)) {
 		msvcrt_alloc_buffer(file);
 		file->_ptr++;
@@ -2991,6 +2993,7 @@ int MSVCRT_ungetc(int c, MSVCRT_FILE * file)
 		file->_ptr--;
 		*file->_ptr=c;
 		file->_cnt++;
+		MSVCRT_clearerr(file);
 		return c;
 	}
 	return MSVCRT_EOF;

dlls/msvcrt/tests/file.c

@@ -2,6 +2,7 @@
  * Unit test suite for file functions
  *
  * Copyright 2002 Bill Currie
+ * Copyright 2005 Paul Rupe
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -59,6 +60,7 @@ static void test_fileops( void )
     int fd;
     FILE *file;
     fpos_t pos;
+    int i, c;
 
     fd = open ("fdopen.tst", O_WRONLY | O_CREAT | O_BINARY, _S_IREAD |_S_IWRITE);
     write (fd, outbuffer, sizeof (outbuffer));
@@ -78,6 +80,26 @@ static void test_fileops( void )
     ok(buffer[0] == outbuffer[strlen(outbuffer)-1],"fgets exchanged chars\n");
 
     rewind(file);
+    for (i = 0, c = EOF; i < sizeof(outbuffer); i++)
+    {
+        ok((c = fgetc(file)) == outbuffer[i], "fgetc returned wrong data\n");
+    }
+    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
+    ok(feof(file), "feof did not return EOF\n");
+    ok(ungetc(c, file) == EOF, "ungetc(EOF) did not return EOF\n");
+    ok(feof(file), "feof after ungetc(EOF) did not return EOF\n");
+    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
+    c = outbuffer[sizeof(outbuffer) - 1];
+    ok(ungetc(c, file) == c, "ungetc did not return its input\n");
+    ok(!feof(file), "feof after ungetc returned EOF\n");
+    ok((c = fgetc(file)) != EOF, "getc after ungetc returned EOF\n");
+    ok(c == outbuffer[sizeof(outbuffer) - 1],
+       "getc did not return ungetc'd data\n");
+    ok(!feof(file), "feof after getc returned EOF prematurely\n");
+    ok((c = fgetc(file)) == EOF, "getc did not return EOF\n");
+    ok(feof(file), "feof after getc did not return EOF\n");
+
+    rewind(file);
     ok(fgetpos(file,&pos) == 0, "fgetpos failed unexpected\n");
     ok(pos == 0, "Unexpected result of fgetpos 0x%Lx\n", pos);
     pos = (ULONGLONG)sizeof (outbuffer);