From: Piotr Caban <piotr.caban@gmail.com>
Subject: Re: [PATCH] msvcrt: Fix fscanf return when EOF is immediately after an end of line.
Message-Id: <5bcb4ab2-17a0-0d14-4ca0-73c4b7094991@gmail.com>
Date: Thu, 17 Oct 2019 13:22:00 +0200
In-Reply-To: <CAEU2+vqfhvQRLW9wTzRNVFPA9ep-BjDb36Tj5E3M3wwbHBGjbw@mail.gmail.com>
References: <CAEU2+vqfhvQRLW9wTzRNVFPA9ep-BjDb36Tj5E3M3wwbHBGjbw@mail.gmail.com>

Hi Erich,

The implementation part of the patch doesn't look right. I think that it 
should be fixed by %s format reporting error when there's no characters 
to read.

I'm attaching a diff (generated on top of your patch) that shows the 
problems.

Also please use only tests on strings (sscanf) or handle file creation 
failure.

Thanks,
Piotr

diff --git a/dlls/msvcrt/tests/scanf.c b/dlls/msvcrt/tests/scanf.c
index c0d5aa66d1..4759ba291c 100644
--- a/dlls/msvcrt/tests/scanf.c
+++ b/dlls/msvcrt/tests/scanf.c
@@ -27,7 +27,7 @@ static void test_fscanf( void )
     static const char file_name[] = "fprintf.tst";
     static const char contents[] =
         "line1\n"
-        "line2\n"
+        "line2 "
     ;
     char buf[1024];
     FILE *fp;
@@ -77,6 +77,14 @@ static void test_sscanf( void )
     ret = p_sscanf(buffer, "%d", &result);
     ok( ret == EOF,"sscanf returns %x instead of %x\n", ret, EOF );
 
+    ret = p_sscanf(" \t\n\n", "%s", buffer);
+    ok(ret == -1, "ret = %d\n", ret);
+
+    buffer1[0] = 'a';
+    ret = p_sscanf("test\n", "%s%c", buffer, buffer1);
+    ok(ret == 2, "ret = %d\n", ret);
+    ok(buffer1[0] == '\n', "buffer1[0] = %d\n", buffer1[0]);
+
     /* check %p */
     ok( p_sscanf("000000000046F170", "%p", &ptr) == 1, "sscanf failed\n"  );
     ok( ptr == (void *)0x46F170,"sscanf reads %p instead of %x\n", ptr, 0x46F170 );