diff --git a/CHANGES b/CHANGES
index 1532e3da7..9ccbaf5c6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -200,7 +200,7 @@ version 0.98 [January, 1998]
       PNG_TIME_RFC1152_SUPPORTED macro to PNG_TIME_RFC1123_SUPPORTED
    added png_invert_alpha capability (Glenn R-P -- suggestion by Jon Vincent)
    changed srgb_intent from png_byte to int to avoid compiler bugs
-version 0.99 [January, 1998]
+version 0.99 [January 30, 1998]
    free info_ptr->text instead of end_info_ptr->text in pngread.c (John Bowler)
    fixed a longstanding "packswap" bug in pngtrans.c
    fixed some inconsistencies in pngconf.h that prevented compiling with
@@ -213,3 +213,6 @@ version 0.99 [January, 1998]
    added TARGET_MACOS similar to zlib-1.0.8
    define PNG_ALWAYS_EXTERN when __MWERKS__ && WIN32 are defined
    added type casting to all png_malloc() function calls
+version 0.99a [January 31, 1998]
+   added type casts and parentheses to all returns that return a value.(Tim W.)
+
diff --git a/README b/README
index 466c28cc4..bf0c9dd76 100644
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-[NOTE:  this is still beta version 0.99; the text below has already
+[NOTE:  this is still beta version 0.99a; the text below has already
  been updated in anticipation of the imminent 1.0 release.]
 
 
diff --git a/libpng.txt b/libpng.txt
index 13af52e9c..39b6e34ac 100644
--- a/libpng.txt
+++ b/libpng.txt
@@ -1,9 +1,9 @@
 libpng.txt - a description on how to use and modify libpng
 
-   libpng version 0.99
+   libpng version 0.99a
    Updated and distributed by Glenn Randers-Pehrson <randeg@alumni.rpi.edu>
    Copyright (c) 1998, Glenn Randers-Pehrson
-   January 30, 1998
+   January 31, 1998
 
       based on:
 
diff --git a/png.c b/png.c
index 4455009ab..8a6b7cf16 100644
--- a/png.c
+++ b/png.c
@@ -1,12 +1,12 @@
 
 /* png.c - location for general purpose libpng functions
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
@@ -16,7 +16,7 @@
 /* Version information for C files.  This had better match the version
  * string defined in png.h.
  */
-char png_libpng_ver[5] = "0.99";
+char png_libpng_ver[6] = "0.99";
 
 /* Place to hold the signature string for a PNG file. */
 png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
@@ -103,15 +103,15 @@ png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
    if (num_to_check > 8)
       num_to_check = 8;
    else if (num_to_check < 1)
-      return 0;
+      return (0);
 
    if (start > 7)
-      return 0;
+      return (0);
 
    if (start + num_to_check > 8)
       num_to_check = 8 - start;
 
-   return (png_memcmp(&sig[start], &png_sig[start], num_to_check));
+   return ((int)(png_memcmp(&sig[start], &png_sig[start], num_to_check)));
 }
 
 /* (Obsolete) function to check signature bytes.  It does not allow one
@@ -121,7 +121,7 @@ png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
 int
 png_check_sig(png_bytep sig, int num)
 {
-  return !png_sig_cmp(sig, (png_size_t)0, (png_size_t)num);
+  return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
 }
 
 /* Function to allocate memory for zlib. */
@@ -143,7 +143,7 @@ png_zalloc(voidpf png_ptr, uInt items, uInt size)
    {
       png_memset(ptr, 0, (png_size_t)num_bytes);
    }
-   return (voidpf)(ptr);
+   return ((voidpf)ptr);
 }
 
 /* function to free memory for zlib */
@@ -205,7 +205,7 @@ png_create_info_struct(png_structp png_ptr)
       png_info_init(info_ptr);
    }
 
-   return info_ptr;
+   return (info_ptr);
 }
 
 /* This function frees the memory associated with a single info struct.
@@ -286,7 +286,7 @@ png_info_destroy(png_structp png_ptr, png_infop info_ptr)
 png_voidp
 png_get_io_ptr(png_structp png_ptr)
 {
-   return png_ptr->io_ptr;
+   return (png_ptr->io_ptr);
 }
 
 #if !defined(PNG_NO_STDIO)
diff --git a/png.h b/png.h
index e8def21a3..cb7c7cc7c 100644
--- a/png.h
+++ b/png.h
@@ -1,12 +1,12 @@
 
 /* png.h - header file for PNG reference library
  *
- * libpng 0.99 beta
+ * libpng 0.99a beta
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998 Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * Note about libpng version numbers:
  *
@@ -27,6 +27,7 @@
  *      0.97c                     0.97      2.0.97
  *      0.98                      0.98      2.0.98
  *      0.99                      0.99      2.0.99
+ *      0.99a                     0.99      2.0.99
  *      1.0                       1.00      2.1.0
  *
  *    Henceforth the source version will match the shared-library minor
diff --git a/pngconf.h b/pngconf.h
index e89bfce03..f14f0e13a 100644
--- a/pngconf.h
+++ b/pngconf.h
@@ -1,12 +1,12 @@
 
 /* pngconf.c - machine configurable file for libpng
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 /* Any machine specific code is near the front of this file, so if you
diff --git a/pngerror.c b/pngerror.c
index 5335e98c1..15edb72ff 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -1,12 +1,12 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file provides a location for all error handling.  Users which
  * need special error handling are expected to write replacement functions
@@ -167,7 +167,7 @@ png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
 png_voidp
 png_get_error_ptr(png_structp png_ptr)
 {
-   return png_ptr->error_ptr;
+   return ((png_voidp)png_ptr->error_ptr);
 }
 
 
diff --git a/pngget.c b/pngget.c
index 4dd3286e6..d24132753 100644
--- a/pngget.c
+++ b/pngget.c
@@ -1,12 +1,12 @@
 
 /* pngget.c - retrieval of values from info struct
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
@@ -126,14 +126,14 @@ png_get_pixel_aspect_ratio(png_structp png_ptr, png_infop info_ptr)
    {
       png_debug1(1, "in %s retrieval function\n", "png_get_aspect_ratio");
       if (info_ptr->x_pixels_per_unit == 0)
-         return NULL;
+         return (0.0);
       else
-         return (float)info_ptr->y_pixels_per_unit
-            /(float)info_ptr->x_pixels_per_unit;
+         return ((float)info_ptr->y_pixels_per_unit
+            /(float)info_ptr->x_pixels_per_unit);
    }
    else
 #endif
-      return (0);
+      return (0.0);
 }
 
 png_uint_32
diff --git a/pngmem.c b/pngmem.c
index e3f317120..cbc83c507 100644
--- a/pngmem.c
+++ b/pngmem.c
@@ -1,11 +1,11 @@
 /* pngmem.c - stub functions for memory allocation
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file provides a location for all memory allocation.  Users which
  * need special memory handling are expected to modify the code in this file
@@ -42,7 +42,7 @@ png_create_struct(int type)
    else if (type == PNG_STRUCT_PNG)
      size = sizeof(png_struct);
    else
-     return (png_voidp)NULL;
+     return ((png_voidp)NULL);
 
    if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
    {
@@ -88,7 +88,7 @@ PNG_MALLOC(png_structp png_ptr, png_uint_32 size)
 {
    png_voidp ret;
    if (png_ptr == NULL || size == 0)
-      return ((voidp)NULL);
+      return ((png_voidp)NULL);
 
 #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
@@ -177,7 +177,7 @@ PNG_MALLOC(png_structp png_ptr, png_uint_32 size)
       png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
    }
 
-   return ret;
+   return (ret);
 }
 
 /* free a pointer allocated by PNG_MALLOC().  In the default
@@ -234,7 +234,7 @@ png_create_struct(int type)
    else if (type == PNG_STRUCT_PNG)
       size = sizeof(png_struct);
    else
-      return (png_voidp)NULL;
+      return ((png_voidp)NULL);
 
 #if defined(__TURBOC__) && !defined(__FLAT__)
    if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
@@ -286,7 +286,7 @@ PNG_MALLOC(png_structp png_ptr, png_uint_32 size)
 {
    png_voidp ret;
    if (png_ptr == NULL || size == 0)
-      return (NULL);
+      return ((png_voidp)NULL);
 
 #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
@@ -308,7 +308,7 @@ PNG_MALLOC(png_structp png_ptr, png_uint_32 size)
       png_error(png_ptr, "Out of Memory");
    }
 
-   return ret;
+   return (ret);
 }
 
 /* Free a pointer allocated by PNG_MALLOC().  In the default
diff --git a/pngpread.c b/pngpread.c
index 100e2baf1..647ad10d6 100644
--- a/pngpread.c
+++ b/pngpread.c
@@ -1,12 +1,12 @@
 
 /* pngpread.c - read a png file in push mode
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
diff --git a/pngread.c b/pngread.c
index 9dbae725d..9d83fb7f5 100644
--- a/pngread.c
+++ b/pngread.c
@@ -1,12 +1,12 @@
 
 /* pngread.c - read a PNG file
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file contains routines that an application calls directly to
  * read a PNG file or stream.
diff --git a/pngrio.c b/pngrio.c
index 18afee3f4..7926b9e87 100644
--- a/pngrio.c
+++ b/pngrio.c
@@ -1,12 +1,12 @@
 
 /* pngrio.c - functions for data input
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file provides a location for all input.  Users which need
  * special handling are expected to write a function which has the same
diff --git a/pngrtran.c b/pngrtran.c
index fac55d7e5..77098afcd 100644
--- a/pngrtran.c
+++ b/pngrtran.c
@@ -1,12 +1,12 @@
 
 /* pngrtran.c - transforms the data in a row for PNG readers
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file contains functions optionally called by an application 
  * in order to tell libpng how to handle data when reading a PNG.
diff --git a/pngrutil.c b/pngrutil.c
index 73e1a53a5..bd6944a79 100644
--- a/pngrutil.c
+++ b/pngrutil.c
@@ -1,12 +1,12 @@
 
 /* pngrutil.c - utilities to read a PNG file
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file contains routines which are only called from within
  * libpng itself during the course of reading an image.
@@ -27,7 +27,7 @@ png_get_uint_32(png_bytep buf)
       ((png_uint_32)(*(buf + 2)) << 8) +
       (png_uint_32)(*(buf + 3));
 
-   return i;
+   return (i);
 }
 
 #if defined(PNG_READ_pCAL_SUPPORTED)
@@ -44,7 +44,7 @@ png_get_int_32(png_bytep buf)
       ((png_int_32)(*(buf + 2)) << 8) +
       (png_int_32)(*(buf + 3));
 
-   return i;
+   return (i);
 }
 #endif /* PNG_READ_pCAL_SUPPORTED */
 
@@ -57,7 +57,7 @@ png_get_uint_16(png_bytep buf)
    i = (png_uint_16)(((png_uint_16)(*buf) << 8) +
       (png_uint_16)(*(buf + 1)));
 
-   return i;
+   return (i);
 }
 #endif /* PNG_READ_BIG_ENDIAN_SUPPORTED */
 
@@ -100,10 +100,10 @@ png_crc_finish(png_structp png_ptr, png_uint_32 skip)
       {
          png_chunk_error(png_ptr, "CRC error");
       }
-      return 1;
+      return (1);
    }
 
-   return 0;
+   return (0);
 }
 
 /* Compare the CRC stored in the PNG file with that calculated by libpng from
@@ -132,10 +132,10 @@ png_crc_error(png_structp png_ptr)
    if (need_crc)
    {
       crc = png_get_uint_32(crc_bytes);
-      return (crc != png_ptr->crc);
+      return ((int)(crc != png_ptr->crc));
    }
    else
-      return 0;
+      return (0);
 }
 
 
diff --git a/pngset.c b/pngset.c
index f4fbb6568..502013e45 100644
--- a/pngset.c
+++ b/pngset.c
@@ -1,12 +1,12 @@
 
 /* pngset.c - storage of image information into info struct
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * The functions here are used during reads to store data from the file
  * into the info struct, and during writes to store application data
diff --git a/pngtest.c b/pngtest.c
index 1e69f0d4a..5c12f1f55 100644
--- a/pngtest.c
+++ b/pngtest.c
@@ -1,12 +1,12 @@
 
 /* pngtest.c - a simple test program to test libpng
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This program reads in a PNG image, writes it out again, and then
  * compares the two files.  If the files are identical, this shows that
@@ -281,10 +281,10 @@ png_voidp
 png_malloc(png_structp png_ptr, png_uint_32 size) {
    if (png_ptr == NULL) {
       fprintf(STDERR, "NULL pointer to memory allocator\n");
-      return NULL;
+      return (NULL);
    }
    if (size == 0)
-      return NULL;
+      return (NULL);
 
    /* This calls the library allocator twice, once to get the requested
       buffer and once to get a new free list entry. */
@@ -299,7 +299,7 @@ png_malloc(png_structp png_ptr, png_uint_32 size) {
       pinformation = pinfo;
       /* Make sure the caller isn't assuming zeroed memory. */
       png_memset(pinfo->pointer, 0xdd, pinfo->size);
-      return pinfo->pointer;
+      return ((png_voidp)pinfo->pointer);
    }
 }
 
@@ -369,14 +369,14 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
    if ((fpin = fopen(inname, "rb")) == NULL)
    {
       fprintf(STDERR, "Could not find input file %s\n", inname);
-      return 1;
+      return (1);
    }
 
    if ((fpout = fopen(outname, "wb")) == NULL)
    {
       fprintf(STDERR, "Could not open output file %s\n", outname);
       fclose(fpin);
-      return 1;
+      return (1);
    }
 
    png_debug(0, "Allocating read and write structures\n");
@@ -409,7 +409,7 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       png_destroy_write_struct(&write_ptr, &write_info_ptr);
       fclose(fpin);
       fclose(fpout);
-      return 1;
+      return (1);
    }
 
    png_debug(0, "Setting jmpbuf for write struct\n");
@@ -425,7 +425,7 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       png_destroy_write_struct(&write_ptr, &write_info_ptr);
       fclose(fpin);
       fclose(fpout);
-      return 1;
+      return (1);
    }
 
 #ifdef USE_FAR_KEYWORD
@@ -621,7 +621,7 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
       png_destroy_write_struct(&write_ptr, &write_info_ptr);
       fclose(fpin);
       fclose(fpout);
-      return 1;
+      return (1);
    }
 
    num_pass = png_set_interlace_handling(read_ptr);
@@ -663,14 +663,14 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
    if ((fpin = fopen(inname, "rb")) == NULL)
    {
       fprintf(STDERR, "Could not find file %s\n", inname);
-      return 1;
+      return (1);
    }
 
    if ((fpout = fopen(outname, "rb")) == NULL)
    {
       fprintf(STDERR, "Could not find file %s\n", outname);
       fclose(fpin);
-      return 1;
+      return (1);
    }
 
    while (1)
@@ -686,7 +686,7 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
                  inname, outname);
          fclose(fpin);
          fclose(fpout);
-         return 1;
+         return (1);
       }
 
       if (!num_in)
@@ -697,14 +697,14 @@ int test_one_file(PNG_CONST char *inname, PNG_CONST char *outname)
          fprintf(STDERR, "Files %s and %s are different\n", inname, outname);
          fclose(fpin);
          fclose(fpout);
-         return 1;
+         return (1);
       }
    }
 
    fclose(fpin);
    fclose(fpout);
 
-   return 0;
+   return (0);
 }
 
 /* input and output filenames */
@@ -867,5 +867,5 @@ main(int argc, char *argv[])
       fprintf(STDERR, "libpng passes test\n");
    else
       fprintf(STDERR, "libpng FAILS test\n");
-   return ierror != 0;
+   return ((int)(ierror != 0));
 }
diff --git a/pngtrans.c b/pngtrans.c
index 5d6033997..28177d29d 100644
--- a/pngtrans.c
+++ b/pngtrans.c
@@ -1,12 +1,12 @@
 
 /* pngtrans.c - transforms the data in a row (used by both readers and writers)
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
@@ -77,10 +77,10 @@ png_set_interlace_handling(png_structp png_ptr)
    if (png_ptr->interlaced)
    {
       png_ptr->transformations |= PNG_INTERLACE;
-      return 7;
+      return (7);
    }
 
-   return 1;
+   return (1);
 }
 #endif
 
diff --git a/pngwio.c b/pngwio.c
index aca29bd32..2358a02c1 100644
--- a/pngwio.c
+++ b/pngwio.c
@@ -1,12 +1,12 @@
 
 /* pngwio.c - functions for data output
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  *
  * This file provides a location for all output.  Users which need
  * special handling are expected to write functions which have the same
diff --git a/pngwrite.c b/pngwrite.c
index db6c82620..d56cc426a 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -1,12 +1,12 @@
    
 /* pngwrite.c - general routines to write a PNG file
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 /* get internal access to png.h */
@@ -249,7 +249,7 @@ png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
                ptime->year, ptime->hour % 24, ptime->minute % 60,
                ptime->second % 61);
 #endif
-   return png_ptr->time_buffer;
+   return ((png_charp)png_ptr->time_buffer);
 }
 #endif /* PNG_TIME_RFC1123_SUPPORTED */
 
@@ -289,7 +289,7 @@ png_create_write_struct(png_const_charp user_png_ver, voidp error_ptr,
    png_debug(1, "in png_create_write_struct\n");
    if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
    {
-      return (png_structp)NULL;
+      return ((png_structp)NULL);
    }
 #ifdef USE_FAR_KEYWORD
    if (setjmp(jmpbuf))
@@ -299,7 +299,7 @@ png_create_write_struct(png_const_charp user_png_ver, voidp error_ptr,
    {
       png_free(png_ptr, png_ptr->zbuf);
       png_destroy_struct(png_ptr);
-      return (png_structp)NULL;
+      return ((png_structp)NULL);
    }
 #ifdef USE_FAR_KEYWORD
    png_memcpy(png_ptr->jmpbuf,jmpbuf,sizeof(jmp_buf));
@@ -329,7 +329,7 @@ png_create_write_struct(png_const_charp user_png_ver, voidp error_ptr,
       1, NULL, NULL);
 #endif
 
-   return (png_ptr);
+   return ((png_structp)png_ptr);
 }
 
 
diff --git a/pngwtran.c b/pngwtran.c
index dd14abc77..97886ba28 100644
--- a/pngwtran.c
+++ b/pngwtran.c
@@ -1,12 +1,12 @@
 
 /* pngwtran.c - transforms the data in a row for PNG writers
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
diff --git a/pngwutil.c b/pngwutil.c
index fcc7eb0d0..22f7797db 100644
--- a/pngwutil.c
+++ b/pngwutil.c
@@ -1,12 +1,12 @@
 
 /* pngwutil.c - utilities to write a PNG file
  *
- * libpng 0.99
+ * libpng 0.99a
  * For conditions of distribution and use, see copyright notice in png.h
  * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  * Copyright (c) 1996, 1997 Andreas Dilger
  * Copyright (c) 1998, Glenn Randers-Pehrson
- * January 30, 1998
+ * January 31, 1998
  */
 
 #define PNG_INTERNAL
@@ -599,7 +599,7 @@ png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
    if (key == NULL || (key_len = png_strlen(key)) == 0)
    {
       png_chunk_warning(png_ptr, "zero length keyword");
-      return 0;
+      return ((png_size_t)0);
    }
 
    png_debug1(2, "Keyword to be checked is '%s'\n", key);
@@ -688,7 +688,7 @@ png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
       key_len = 79;
    }
 
-   return key_len;
+   return (key_len);
 }
 #endif