diff --git a/src/ChangeLog b/src/ChangeLog
index 421bf321a..47f0e3082 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2002-11-13  Pavel Roskin  <proski@gnu.org>
 
+	* man2hlp.c (persistent_fread): Return error for len <= 0.
+	(persistent_fwrite): Likewise.
+	(main): Check the result of the second ftell().
+
 	* cmd.h: Fully exclude WPanel from public interfaces of cmd.c.
 	* cmd.c: All commands operate on current panels.
 	(get_a_panel): Remove.
diff --git a/src/man2hlp.c b/src/man2hlp.c
index cca2df845..078b6547f 100644
--- a/src/man2hlp.c
+++ b/src/man2hlp.c
@@ -74,6 +74,9 @@ persistent_fread (void *data, size_t len, FILE *stream)
     size_t bytes_done = 0;
     char *ptr = (char *) data;
 
+    if (len <= 0)
+	return 0;
+
     while (bytes_done < len) {
 	count = len - bytes_done;
 	if (count > MAX_STREAM_BLOCK)
@@ -102,6 +105,9 @@ persistent_fwrite (const void *data, size_t len, FILE *stream)
     size_t bytes_done = 0;
     const char *ptr = (const char *) data;
 
+    if (len <= 0)
+	return 0;
+
     while (bytes_done < len) {
 	count = len - bytes_done;
 	if (count > MAX_STREAM_BLOCK)
@@ -780,6 +786,11 @@ main (int argc, char **argv)
     }
 
     cont_start = ftell (f_out);
+    if (cont_start <= 0) {
+	perror (c_out);
+	return 1;
+    }
+
     if (topics)
 	fprintf (f_out, "\004[Contents]\n%s\n\n", topics);
     else
@@ -830,7 +841,9 @@ main (int argc, char **argv)
     }
 
     file_end = ftell (f_out);
-    if (file_end <= 0) {
+
+    /* Sanity check */
+    if ((file_end <= 0) || (file_end - cont_start <= 0)) {
 	perror (c_out);
 	return 1;
     }