diff --git a/tools/tiffcmp.c b/tools/tiffcmp.c
index 7b764883..041d6a2d 100644
--- a/tools/tiffcmp.c
+++ b/tools/tiffcmp.c
@@ -39,6 +39,13 @@
 
 #include "tiffio.h"
 
+#ifndef EXIT_SUCCESS
+#define EXIT_SUCCESS 0
+#endif
+#ifndef EXIT_FAILURE
+#define EXIT_FAILURE 1
+#endif
+
 #ifndef HAVE_GETOPT
 extern int getopt(int argc, char * const argv[], const char *optstring);
 #endif
@@ -51,7 +58,7 @@ static	uint16 sampleformat = SAMPLEFORMAT_UINT;
 static	uint32 imagewidth;
 static	uint32 imagelength;
 
-static	void usage(void);
+static	void usage(int code);
 static	int tiffcmp(TIFF*, TIFF*);
 static	int cmptags(TIFF*, TIFF*);
 static	int ContigCompare(int, uint32, unsigned char*, unsigned char*, tsize_t);
@@ -61,6 +68,12 @@ static	void PrintFloatDiff(uint32, int, uint32, double, double);
 
 static	void leof(const char*, uint32, int);
 
+/*
+ * exit with status :
+ * 0    No differences were found.
+ * 1    Differences were found.
+ * >1   An error occurred.
+ */
 int
 main(int argc, char* argv[])
 {
@@ -71,7 +84,7 @@ main(int argc, char* argv[])
 	extern char* optarg;
 #endif
 
-	while ((c = getopt(argc, argv, "ltz:")) != -1)
+	while ((c = getopt(argc, argv, "ltz:h")) != -1)
 		switch (c) {
 		case 'l':
 			stopondiff = 0;
@@ -82,18 +95,20 @@ main(int argc, char* argv[])
 		case 't':
 			stoponfirsttag = 0;
 			break;
+		case 'h':
+			usage(EXIT_SUCCESS);
 		case '?':
-			usage();
+			usage(2);
 			/*NOTREACHED*/
 		}
 	if (argc - optind < 2)
-		usage();
+		usage(2);
 	tif1 = TIFFOpen(argv[optind], "r");
 	if (tif1 == NULL)
-		return (-1);
+		return (2);
 	tif2 = TIFFOpen(argv[optind+1], "r");
 	if (tif2 == NULL)
-		return (-2);
+		return (2);
 	dirnum = 0;
 	while (tiffcmp(tif1, tif2)) {
 		if (!TIFFReadDirectory(tif1)) {
@@ -115,7 +130,7 @@ main(int argc, char* argv[])
 	return (0);
 }
 
-char* stuff[] = {
+static const char* stuff[] = {
 "usage: tiffcmp [options] file1 file2",
 "where options are:",
 " -l		list each byte of image data that differs between the files",
@@ -125,16 +140,15 @@ NULL
 };
 
 static void
-usage(void)
+usage(int code)
 {
-	char buf[BUFSIZ];
 	int i;
+	FILE * out = (code == EXIT_SUCCESS) ? stdout : stderr;
 
-	setbuf(stderr, buf);
-        fprintf(stderr, "%s\n\n", TIFFGetVersion());
+        fprintf(out, "%s\n\n", TIFFGetVersion());
 	for (i = 0; stuff[i] != NULL; i++)
-		fprintf(stderr, "%s\n", stuff[i]);
-	exit(-1);
+		fprintf(out, "%s\n", stuff[i]);
+	exit(code);
 }
 
 #define	checkEOF(tif, row, sample) { \
@@ -177,7 +191,7 @@ tiffcmp(TIFF* tif1, TIFF* tif2)
 	buf2 = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(tif2));
 	if (buf1 == NULL || buf2 == NULL) {
 		fprintf(stderr, "No space for scanline buffers\n");
-		exit(-1);
+		exit(2);
 	}
 	if (config1 != config2 && bitspersample != 8 && samplesperpixel > 1) {
 		fprintf(stderr,