diff --git a/dlpisubs.c b/dlpisubs.c
index 5f1a9bfc5f..671302f16e 100644
--- a/dlpisubs.c
+++ b/dlpisubs.c
@@ -193,7 +193,7 @@ pcap_process_pkts(pcap_t *p, pcap_handler callback, u_char *user,
 			if (pkthdr.caplen > p->snapshot)
 				pkthdr.caplen = p->snapshot;
 			(*callback)(user, &pkthdr, pk);
-			if (++n >= count && count >= 0) {
+			if (++n >= count && !PACKET_COUNT_IS_UNLIMITED(count)) {
 				p->cc = ep - bufp;
 				p->bp = bufp;
 				return (n);
diff --git a/pcap-bpf.c b/pcap-bpf.c
index bc37639ebd..250298a78d 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -1037,7 +1037,7 @@ pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 #endif
 			(*callback)(user, &pkthdr, datap);
 			bp += BPF_WORDALIGN(caplen + hdrlen);
-			if (++n >= cnt && cnt > 0) {
+			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 				p->bp = bp;
 				p->cc = ep - bp;
 				/*
diff --git a/pcap-dag.c b/pcap-dag.c
index 247bee8774..70a6d6c204 100644
--- a/pcap-dag.c
+++ b/pcap-dag.c
@@ -579,7 +579,7 @@ dag_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 	
 			/* Only count packets that pass the filter, for consistency with standard Linux behaviour. */
 			processed++;
-			if (processed == cnt && cnt > 0)
+			if (processed == cnt && !PACKET_COUNT_IS_UNLIMITED(cnt))
 			{
 				/* Reached the user-specified limit. */
 				return cnt;
diff --git a/pcap-dos.c b/pcap-dos.c
index 15a9a6803b..cecc73cede 100644
--- a/pcap-dos.c
+++ b/pcap-dos.c
@@ -335,7 +335,7 @@ pcap_read_dos (pcap_t *p, int cnt, pcap_handler callback, u_char *data)
   struct pcap_dos *pd = p->priv;
   int rc, num = 0;
 
-  while (num <= cnt || (cnt < 0))
+  while (num <= cnt || PACKET_COUNT_IS_UNLIMITED(cnt))
   {
     if (p->fd <= 0)
        return (-1);
diff --git a/pcap-int.h b/pcap-int.h
index 08bbcc3d84..0c27ec7ac4 100644
--- a/pcap-int.h
+++ b/pcap-int.h
@@ -336,6 +336,12 @@ extern int snprintf (char *, size_t, const char *, ...);
 extern int vsnprintf (char *, size_t, const char *, va_list ap);
 #endif
 
+/*
+ * Does the packet count argument to a module's read routine say
+ * "supply packets until you run out of packets"?
+ */
+#define PACKET_COUNT_IS_UNLIMITED(count)	((count) <= 0)
+
 /*
  * Routines that most pcap implementations can use for non-blocking mode.
  */
diff --git a/pcap-linux.c b/pcap-linux.c
index 565abd3ba8..7a05ff2931 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -4333,7 +4333,7 @@ pcap_read_linux_mmap_v1(pcap_t *handle, int max_packets, pcap_handler callback,
 
 	/* non-positive values of max_packets are used to require all
 	 * packets currently available in the ring */
-	while ((pkts < max_packets) || (max_packets <= 0)) {
+	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
 		union thdr h;
 
 		h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
@@ -4391,7 +4391,7 @@ pcap_read_linux_mmap_v2(pcap_t *handle, int max_packets, pcap_handler callback,
 
 	/* non-positive values of max_packets are used to require all
 	 * packets currently available in the ring */
-	while ((pkts < max_packets) || (max_packets <= 0)) {
+	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
 		union thdr h;
 
 		h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
@@ -4460,7 +4460,7 @@ pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
 
 	/* non-positive values of max_packets are used to require all
 	 * packets currently available in the ring */
-	while ((pkts < max_packets) || (max_packets <= 0)) {
+	while ((pkts < max_packets) || PACKET_COUNT_IS_UNLIMITED(max_packets)) {
 		if (handlep->current_packet == NULL) {
 			h.raw = pcap_get_ring_frame(handle, TP_STATUS_USER);
 			if (!h.raw)
@@ -4471,7 +4471,7 @@ pcap_read_linux_mmap_v3(pcap_t *handle, int max_packets, pcap_handler callback,
 		}
 		int packets_to_read = handlep->packets_left;
 
-		if (max_packets > 0 && packets_to_read > max_packets) {
+		if (!PACKET_COUNT_IS_UNLIMITED(max_packets) && packets_to_read > max_packets) {
 			packets_to_read = max_packets;
 		}
 
diff --git a/pcap-nit.c b/pcap-nit.c
index 60521a43ad..40e640cdc6 100644
--- a/pcap-nit.c
+++ b/pcap-nit.c
@@ -189,7 +189,7 @@ pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 			h.len = nh->nh_wirelen;
 			h.caplen = caplen;
 			(*callback)(user, &h, cp);
-			if (++n >= cnt && cnt > 0) {
+			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 				p->cc = ep - bp;
 				p->bp = bp;
 				return (n);
diff --git a/pcap-pf.c b/pcap-pf.c
index 9a79bdf5f4..8de6e58f63 100644
--- a/pcap-pf.c
+++ b/pcap-pf.c
@@ -219,7 +219,7 @@ pcap_read_pf(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
 			buflen -= pad;
 			h.caplen = buflen;
 			(*callback)(user, &h, p);
-			if (++n >= cnt && cnt > 0) {
+			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 				pc->cc = cc;
 				pc->bp = bp;
 				return (n);
diff --git a/pcap-snf.c b/pcap-snf.c
index 3709d01cd0..ee6ffa4dcc 100644
--- a/pcap-snf.c
+++ b/pcap-snf.c
@@ -118,7 +118,7 @@ snf_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		return -1;
 
 	n = 0;
-	while (n < cnt || cnt < 0) {
+	while (n < cnt || PACKET_COUNT_IS_UNLIMITED(cnt)) {
 		/*
 		 * Has "pcap_breakloop()" been called?
 		 */
diff --git a/pcap-snit.c b/pcap-snit.c
index 08c587252c..12656b8e5c 100644
--- a/pcap-snit.c
+++ b/pcap-snit.c
@@ -201,7 +201,7 @@ pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 			h.len = nlp->nh_pktlen;
 			h.caplen = caplen;
 			(*callback)(user, &h, cp);
-			if (++n >= cnt && cnt > 0) {
+			if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 				p->cc = ep - bp;
 				p->bp = bp;
 				return (n);
diff --git a/pcap-usb-linux.c b/pcap-usb-linux.c
index e5b76a6316..f0892a7bd9 100644
--- a/pcap-usb-linux.c
+++ b/pcap-usb-linux.c
@@ -908,8 +908,8 @@ usb_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback, u_ch
 			}
 		}
 
-		/* with max_packets <= 0 we stop afer the first chunk*/
-		if ((max_packets <= 0) || (packets == max_packets))
+		/* with max_packets specifying "unlimited" we stop afer the first chunk*/
+		if (PACKET_COUNT_IS_UNLIMITED(max_packets) || (packets == max_packets))
 			break;
 	}
 
diff --git a/pcap-win32.c b/pcap-win32.c
index 5ea10c97ff..87b3fc6ac2 100644
--- a/pcap-win32.c
+++ b/pcap-win32.c
@@ -256,7 +256,7 @@ pcap_read_win32_npf(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		 */
 		(*callback)(user, (struct pcap_pkthdr*)bp, bp + hdrlen);
 		bp += Packet_WORDALIGN(caplen + hdrlen);
-		if (++n >= cnt && cnt > 0) {
+		if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 			p->bp = bp;
 			p->cc = ep - bp;
 			return (n);
@@ -416,7 +416,7 @@ pcap_read_win32_dag(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		header = (dag_record_t*)((char*)header + erf_record_len);
 
 		/* Stop if the number of packets requested by user has been reached*/
-		if (++n >= cnt && cnt > 0) 
+		if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) 
 		{
 			p->bp = (char*)header;
 			p->cc = endofbuf - (char*)header;
diff --git a/pcap.c b/pcap.c
index faa9762b73..83d4bb1571 100644
--- a/pcap.c
+++ b/pcap.c
@@ -858,7 +858,7 @@ pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 		}
 		if (n <= 0)
 			return (n);
-		if (cnt > 0) {
+		if (!PACKET_COUNT_IS_UNLIMITED(cnt)) {
 			cnt -= n;
 			if (cnt <= 0)
 				return (0);