make kernel_pid_t comparisons consistent

drivers/at86rf231/at86rf231_rx.c

@@ -61,7 +61,7 @@ void at86rf231_rx_handler(void)
 #endif
 
         /* notify transceiver thread if any */
-        if (transceiver_pid > KERNEL_PID_UNDEF) {
+        if (transceiver_pid != KERNEL_PID_UNDEF) {
             msg_t m;
             m.type = (uint16_t) RCV_PKT_AT86RF231;
             m.content.value = rx_buffer_next;

drivers/cc110x_ng/cc110x-rx.c

@@ -86,7 +86,7 @@ void cc110x_rx_handler(void)
 #endif
 
         /* notify transceiver thread if any */
-        if (transceiver_pid > KERNEL_PID_UNDEF) {
+        if (transceiver_pid != KERNEL_PID_UNDEF) {
             msg_t m;
             m.type = (uint16_t) RCV_PKT_CC1100;
             m.content.value = rx_buffer_next;

drivers/cc2420/cc2420_rx.c

@@ -78,7 +78,7 @@ void cc2420_rx_handler(void)
 #endif
 
         /* notify transceiver thread if any */
-        if (transceiver_pid > KERNEL_PID_UNDEF) {
+        if (transceiver_pid != KERNEL_PID_UNDEF) {
             msg_t m;
             m.type = (uint16_t) RCV_PKT_CC2420;
             m.content.value = rx_buffer_next;

examples/rpl_udp/helper.c

@@ -123,7 +123,7 @@ void rpl_udp_ignore(int argc, char **argv)
 {
     uint16_t a;
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not runnning.");
         return;
     }

sys/net/network_layer/sixlowpan/lowpan.c

@@ -1794,7 +1794,7 @@ int sixlowpan_lowpan_init(void)
                                        ipv6_process, NULL, "ip_process");
     }
 
-    if (ip_process_pid < 0) {
+    if (ip_process_pid == KERNEL_PID_UNDEF) {
         return 0;
     }
 
@@ -1804,7 +1804,7 @@ int sixlowpan_lowpan_init(void)
                                      PRIORITY_MAIN + 1, CREATE_STACKTEST,
                                      lowpan_context_auto_remove, NULL, "lowpan_context_rem");
 
-    if (contexts_rem_pid < 0) {
+    if (contexts_rem_pid == KERNEL_PID_UNDEF) {
         return 0;
     }
 
@@ -1812,7 +1812,7 @@ int sixlowpan_lowpan_init(void)
                                  PRIORITY_MAIN - 1, CREATE_STACKTEST,
                                  lowpan_transfer, NULL, "lowpan_transfer");
 
-    if (transfer_pid < 0) {
+    if (transfer_pid == KERNEL_PID_UNDEF) {
         return 0;
     }
 

sys/net/transport_layer/destiny/destiny.c

@@ -46,7 +46,7 @@ int destiny_init_transport_layer(void)
                                        PRIORITY_MAIN, CREATE_STACKTEST,
                                        udp_packet_handler, NULL, "udp_packet_handler");
 
-    if (udp_thread_pid < 0) {
+    if (udp_thread_pid == KERNEL_PID_UNDEF) {
         return -1;
     }
 
@@ -66,7 +66,7 @@ int destiny_init_transport_layer(void)
                                        PRIORITY_MAIN, CREATE_STACKTEST,
                                        tcp_packet_handler, NULL, "tcp_packet_handler");
 
-    if (tcp_thread_pid < 0) {
+    if (tcp_thread_pid == KERNEL_PID_UNDEF) {
         return -1;
     }
 

sys/posix/pthread/pthread.c

@@ -117,7 +117,7 @@ int pthread_create(pthread_t *newthread, const pthread_attr_t *attr, void *(*sta
     pthread_thread_t *pt = calloc(1, sizeof(pthread_thread_t));
 
     kernel_pid_t pthread_pid = insert(pt);
-    if (pthread_pid < 0) {
+    if (pthread_pid == KERNEL_PID_UNDEF) {
         free(pt);
         return -1;
     }
@@ -155,7 +155,7 @@ int pthread_create(pthread_t *newthread, const pthread_attr_t *attr, void *(*sta
                                    pthread_start_routine,
                                    pt,
                                    "pthread");
-    if (pt->thread_pid < 0) {
+    if (pt->thread_pid == KERNEL_PID_UNDEF) {
         free(pt->stack);
         free(pt);
         pthread_sched_threads[pthread_pid-1] = NULL;

sys/shell/commands/sc_transceiver.c

@@ -68,7 +68,7 @@ void _transceiver_get_set_address_handler(int argc, char **argv)
     transceiver_command_t tcmd;
     radio_address_t a;
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -147,7 +147,7 @@ void _transceiver_get_set_long_addr_handler(int argc, char **argv)
     transceiver_command_t tcmd;
     transceiver_eui64_t a;
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -183,7 +183,7 @@ void _transceiver_get_set_channel_handler(int argc, char **argv)
     transceiver_command_t tcmd;
     int32_t c;
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -212,7 +212,7 @@ void _transceiver_get_set_channel_handler(int argc, char **argv)
 
 void _transceiver_send_handler(int argc, char **argv)
 {
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -264,7 +264,7 @@ void _transceiver_send_handler(int argc, char **argv)
 /* checked for type safety */
 void _transceiver_monitor_handler(int argc, char **argv)
 {
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -290,7 +290,7 @@ void _transceiver_monitor_handler(int argc, char **argv)
 /* checked for type safety */
 void _transceiver_get_set_pan_handler(int argc, char **argv)
 {
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }
@@ -325,7 +325,7 @@ void _transceiver_get_set_pan_handler(int argc, char **argv)
 void _transceiver_set_ignore_handler(int argc, char **argv)
 {
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Transceiver not initialized");
         return;
     }

sys/transceiver/transceiver.c

@@ -182,7 +182,7 @@ kernel_pid_t transceiver_start(void)
 {
     transceiver_pid = thread_create(transceiver_stack, TRANSCEIVER_STACK_SIZE, PRIORITY_MAIN - 3, CREATE_STACKTEST, run, NULL, "Transceiver");
 
-    if (transceiver_pid < 0) {
+    if (transceiver_pid == KERNEL_PID_UNDEF) {
         puts("Error creating transceiver thread");
     }
 

tests/posix_semaphore/main.c

@@ -71,7 +71,7 @@ static void test1(void)
                                      NULL,
                                      "second");
 
-    if (pid < 0) {
+    if (pid == KERNEL_PID_UNDEF) {
         puts("first: thread create failed");
     }