1 files changed, 130 insertions, 0 deletions
diff --git a/src/pal/tests/palsuite/c_runtime/ungetc/test1/ungetc.cpp b/src/pal/tests/palsuite/c_runtime/ungetc/test1/ungetc.cpp
new file mode 100644
index 0000000000..397e42ac64
--- /dev/null
+++ b/src/pal/tests/palsuite/c_runtime/ungetc/test1/ungetc.cpp
@@ -0,0 +1,130 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+/*=====================================================================
+**
+** Source:  ungetc.c (test 1)
+**
+** Purpose: Tests the PAL implementation of the ungetc function by calling
+**          the function on a write-only file.
+**
+** Dependencies:
+**          fopen
+**          fclose
+**          fseek
+**
+**
+**===================================================================*/
+
+#include <palsuite.h>
+
+
+int __cdecl main(int argc, char *argv[])
+{
+    char szFileName[] = {"test1.tmp"};
+    const char text[] = 
+        {"The quick brown fox jumped over the lazy dog's back."};
+    FILE* pFile = NULL;
+    int nChar = 65; /* 'A' */
+    int nRc = 0;
+    int itemsExpected;
+    int itemsWritten;
+
+    if (0 != PAL_Initialize(argc,argv))
+    {
+        return FAIL;
+    }
+
+    /* create the file */
+    pFile = fopen(szFileName, "w");
+    if (pFile == NULL)
+    {
+        Fail("ungetc: ERROR -> fopen failed to create the file \"%s\""
+            " as write-only.\n",
+            szFileName);
+    }
+
+    /* write to the file */
+    itemsExpected = sizeof(text);
+    itemsWritten = fwrite(text, sizeof(text[0]), sizeof(text), pFile);  
+    if (itemsWritten == 0)
+    {
+        Trace("ungetc: ERROR -> fwrite failed to write to the file \"%s\"\n",
+            szFileName);
+
+        if (fclose(pFile) != 0)
+        {
+            Fail("ungetc: ERROR -> fclose failed to close the file.\n");
+        }
+        Fail("");
+
+    }
+    else if (itemsWritten != itemsExpected) 
+    {
+        Trace("ungetc: ERROR -> fwrite failed to write the correct number "
+            "of characters to the file \"%s\"\n",
+            szFileName);
+
+        if (fclose(pFile) != 0)
+        {
+            Fail("ungetc: ERROR -> fclose failed to close the file.\n");
+        }
+        Fail("");
+    }
+
+    /* Close the file */
+    if (fclose(pFile) != 0)
+    {
+        Fail("ungetc: ERROR -> fclose failed to close the file.\n");
+    }
+
+    /*
+    ** open the file in write only mode and
+    ** attempt to push an unread character back on the stream
+    */
+
+
+    /* open the file write-only */
+    pFile = fopen(szFileName, "a");
+    if (pFile == NULL)
+    {
+        Fail("ungetc: ERROR -> fopen failed to open the file \"%s\""
+            " as write-only.\n",
+            szFileName);
+    }
+
+    /* move the file pointer back to the beginning of the file */
+    if (fseek(pFile, 1, SEEK_SET) != 0)
+    {
+
+        Trace("ungetc: ERROR -> fseek failed to move the file pointer to the "
+            "beginning of the file.\n");
+        if (fclose(pFile) != 0)
+        {
+            Trace("ungetc: ERROR -> fclose failed to close the file.\n");
+        }
+        Fail("");
+    }
+
+    /* call ungetc on a write-only file which should fail */
+    if ((nRc = ungetc(nChar, pFile)) != EOF)
+    {
+        Trace("ungetc: ERROR -> ungetc returned \"%c\" when run on "
+            "an write-only file.\n", nChar);
+        if (fclose(pFile) != 0)
+        {
+            Trace("ungetc: ERROR -> fclose failed to close the file.\n");
+        }
+        Fail("");
+    }
+
+    if (fclose(pFile) != 0)
+    {
+        Fail("ungetc: ERROR -> fclose failed to close the file.\n");
+    }
+
+    
+    PAL_Terminate();
+    return PASS;
+}