diff --git a/configure.ac b/configure.ac
index 47e3279..0e45289 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,7 +13,7 @@ AC_PATH_PROG(PKG_CONFIG, pkg-config)
 
 # Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS([stdlib.h stdint.h])
+AC_CHECK_HEADERS([stdio.h stdlib.h stdint.h stddef.h])
 
 
 # libusb
diff --git a/src/anticol.c b/src/anticol.c
index f05908f..1969dc3 100644
--- a/src/anticol.c
+++ b/src/anticol.c
@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <string.h>
 
@@ -47,7 +48,7 @@ bool transmit_bits(const byte* pbtTx, const uint32_t uiTxBits)
   printf("R: "); print_hex_bits(pbtTx,uiTxBits);
 
   // Transmit the bit frame command, we don't use the arbitrary parity feature
-  if (!nfc_reader_transceive_bits(pdi,pbtTx,uiTxBits,null,abtRx,&uiRxBits,null)) return false;
+  if (!nfc_reader_transceive_bits(pdi,pbtTx,uiTxBits,NULL,abtRx,&uiRxBits,NULL)) return false;
 
   // Show received answer
   printf("T: "); print_hex_bits(abtRx,uiRxBits);
diff --git a/src/defines.h b/src/defines.h
index cddea0e..122ac25 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -21,15 +21,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifndef _LIBNFC_DEFINES_H_
 #define _LIBNFC_DEFINES_H_
 
-// #define DEBUG
+// #define DEBUG   /* DEBUG flag can also be enabled using ./configure --enable-debug */
 
 typedef unsigned char       byte;
-typedef unsigned long       ulong;
-
-#define null 0
 
 typedef void*               dev_spec; // Device connection specification
-#define INVALID_DEVICE_INFO null
+#define INVALID_DEVICE_INFO 0
 #define MAX_FRAME_LEN       264
 #define DEVICE_NAME_LENGTH  256
 
diff --git a/src/dev_acr122.c b/src/dev_acr122.c
index 18e6181..80b8363 100644
--- a/src/dev_acr122.c
+++ b/src/dev_acr122.c
@@ -17,14 +17,16 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 */
+#include "dev_acr122.h"
 
-#include "defines.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
 
 #include <winscard.h>
-#include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include "dev_acr122.h"
+
+#include "defines.h"
 #include "bitutils.h"
 
 // WINDOWS: #define IOCTL_CCID_ESCAPE_SCARD_CTL_CODE SCARD_CTL_CODE(3500)
@@ -53,7 +55,7 @@ static byte abtTxBuf[ACR122_WRAP_LEN+ACR122_COMMAND_LEN] = { 0xFF, 0x00, 0x00, 0
 static byte abtRxCmd[5] = { 0xFF,0xC0,0x00,0x00 };
 static byte uiRxCmdLen = sizeof(abtRxCmd);
 static byte abtRxBuf[ACR122_RESPONSE_LEN];
-static ulong ulRxBufLen;
+static size_t ulRxBufLen;
 static byte abtGetFw[5] = { 0xFF,0x00,0x48,0x00,0x00 };
 static byte abtLed[9] = { 0xFF,0x00,0x40,0x05,0x04,0x00,0x00,0x00,0x00 };
 
@@ -61,7 +63,7 @@ dev_info* dev_acr122_connect(const uint32_t uiIndex)
 {
   char* pacReaders[MAX_READERS];
   char acList[256+64*MAX_READERS];
-  ulong ulListLen = sizeof(acList);
+  size_t ulListLen = sizeof(acList);
   uint32_t uiPos;
   uint32_t uiReaderCount;
   uint32_t uiReader;
@@ -75,10 +77,10 @@ dev_info* dev_acr122_connect(const uint32_t uiIndex)
   memset(acList,0x00,ulListLen);
 
   // Test if context succeeded
-  if (SCardEstablishContext(SCARD_SCOPE_USER,null,null,&(dsa.hCtx)) != SCARD_S_SUCCESS) return INVALID_DEVICE_INFO;
+  if (SCardEstablishContext(SCARD_SCOPE_USER,NULL,NULL,&(dsa.hCtx)) != SCARD_S_SUCCESS) return INVALID_DEVICE_INFO;
 
   // Retrieve the string array of all available pcsc readers
-  if (SCardListReaders(dsa.hCtx,null,acList,(void*)&ulListLen) != SCARD_S_SUCCESS) return INVALID_DEVICE_INFO;
+  if (SCardListReaders(dsa.hCtx,NULL,acList,(void*)&ulListLen) != SCARD_S_SUCCESS) return INVALID_DEVICE_INFO;
   
   #ifdef DEBUG
       printf("Found the following PCSC device(s)\n");
@@ -132,7 +134,7 @@ dev_info* dev_acr122_connect(const uint32_t uiIndex)
     
     // Retrieve the current firmware version
     pcFirmware = dev_acr122_firmware((dev_info*)&dsa);
-    if (strstr(pcFirmware,FIRMWARE_TEXT) != null)
+    if (strstr(pcFirmware,FIRMWARE_TEXT) != NULL)
     {
       // We found a occurence, test if it has the right index
       if (uiDevIndex != 0)
@@ -194,7 +196,7 @@ bool dev_acr122_transceive(const dev_spec ds, const byte* pbtTx, const uint32_t
   {
     if (SCardControl(pdsa->hCard,IOCTL_CCID_ESCAPE_SCARD_CTL_CODE,abtTxBuf,uiTxLen+5,abtRxBuf,ulRxBufLen,(void*)&ulRxBufLen) != SCARD_S_SUCCESS) return false;
   } else {
-    if (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtTxBuf,uiTxLen+5,null,abtRxBuf,(void*)&ulRxBufLen) != SCARD_S_SUCCESS) return false;
+    if (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtTxBuf,uiTxLen+5,NULL,abtRxBuf,(void*)&ulRxBufLen) != SCARD_S_SUCCESS) return false;
   }
 
   if (pdsa->ioCard.dwProtocol == SCARD_PROTOCOL_T0)
@@ -208,7 +210,7 @@ bool dev_acr122_transceive(const dev_spec ds, const byte* pbtTx, const uint32_t
     // Retrieve the response bytes
     abtRxCmd[4] = abtRxBuf[1];
     ulRxBufLen = sizeof(abtRxBuf);
-    if (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtRxCmd,uiRxCmdLen,null,abtRxBuf,(void*)&ulRxBufLen) != SCARD_S_SUCCESS) return false;
+    if (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtRxCmd,uiRxCmdLen,NULL,abtRxBuf,(void*)&ulRxBufLen) != SCARD_S_SUCCESS) return false;
   }
 
   #ifdef DEBUG
@@ -217,7 +219,7 @@ bool dev_acr122_transceive(const dev_spec ds, const byte* pbtTx, const uint32_t
   #endif
 
   // When the answer should be ignored, just return a succesful result
-  if (pbtRx == null || puiRxLen == null) return true;
+  if (pbtRx == NULL || puiRxLen == NULL) return true;
 
   // Make sure we have an emulated answer that fits the return buffer
   if (ulRxBufLen < 4 || (ulRxBufLen-4) > *puiRxLen) return false;
@@ -235,13 +237,13 @@ char* dev_acr122_firmware(const dev_spec ds)
   
   dev_spec_acr122* pdsa = (dev_spec_acr122*)ds;
   static char abtFw[11];
-  ulong ulFwLen = sizeof(abtFw);
+  size_t ulFwLen = sizeof(abtFw);
   memset(abtFw,0x00,ulFwLen);
   if (pdsa->ioCard.dwProtocol == SCARD_PROTOCOL_UNDEFINED)
   {
     uiResult = SCardControl(pdsa->hCard,IOCTL_CCID_ESCAPE_SCARD_CTL_CODE,abtGetFw,sizeof(abtGetFw),abtFw,ulFwLen,(void*)&ulFwLen);
   } else {
-    uiResult = SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtGetFw,sizeof(abtGetFw),null,(byte*)abtFw,(void*)&ulFwLen);
+    uiResult = SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtGetFw,sizeof(abtGetFw),NULL,(byte*)abtFw,(void*)&ulFwLen);
   }
 
   #ifdef DEBUG
@@ -258,12 +260,12 @@ bool dev_acr122_led_red(const dev_spec ds, bool bOn)
 {
   dev_spec_acr122* pdsa = (dev_spec_acr122*)ds;
   byte abtBuf[2];
-  ulong ulBufLen = sizeof(abtBuf);
+  size_t ulBufLen = sizeof(abtBuf);
   if (pdsa->ioCard.dwProtocol == SCARD_PROTOCOL_UNDEFINED)
   {
     return (SCardControl(pdsa->hCard,IOCTL_CCID_ESCAPE_SCARD_CTL_CODE,abtLed,sizeof(abtLed),abtBuf,ulBufLen,(void*)&ulBufLen) == SCARD_S_SUCCESS);
   } else {
-    return (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtLed,sizeof(abtLed),null,(byte*)abtBuf,(void*)&ulBufLen) == SCARD_S_SUCCESS);
+    return (SCardTransmit(pdsa->hCard,&(pdsa->ioCard),abtLed,sizeof(abtLed),NULL,(byte*)abtBuf,(void*)&ulBufLen) == SCARD_S_SUCCESS);
   }
 }
 
diff --git a/src/dev_pn531.c b/src/dev_pn531.c
index 67791e9..ba84cfd 100644
--- a/src/dev_pn531.c
+++ b/src/dev_pn531.c
@@ -20,11 +20,13 @@ Thanks to d18c7db and Okko for example code
 
 */
 
-#include "defines.h"
+#include <stdio.h>
+#include <stddef.h>
 
 #include <usb.h>
-#include <stdio.h>
 #include <string.h>
+
+#include "defines.h"
 #include "dev_pn531.h"
 #include "bitutils.h"
 
@@ -87,7 +89,7 @@ dev_info* dev_pn531_connect(const uint32_t uiIndex)
 
   dsp.uiEndPointIn = 0;
   dsp.uiEndPointOut = 0;
-  dsp.pudh = null;
+  dsp.pudh = NULL;
                                                                         
   usb_init();
   if (usb_find_busses() < 0) return INVALID_DEVICE_INFO;
@@ -234,7 +236,7 @@ bool dev_pn531_transceive(const dev_spec ds, const byte* pbtTx, const uint32_t u
     }
 
     // When the answer should be ignored, just return a succesful result    
-    if(pbtRx == null || puiRxLen == null) return true;
+    if(pbtRx == NULL || puiRxLen == NULL) return true;
 
     // Only succeed when the result is at least 00 00 FF xx Fx Dx xx .. .. .. xx 00 (x = variable)
     if(ret < 9) return false;
diff --git a/src/emulate.c b/src/emulate.c
index 134912a..029ca8f 100644
--- a/src/emulate.c
+++ b/src/emulate.c
@@ -20,6 +20,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <string.h>
 
@@ -36,7 +37,7 @@ byte abtSak       [9] = { 0x08,0xb6,0xdd };
 
 int main(int argc, const char* argv[])
 {                       
-  byte* pbtTx = null;
+  byte* pbtTx = NULL;
   uint32_t uiTxBits;
   
   // Try to open the NFC reader
@@ -68,7 +69,7 @@ int main(int argc, const char* argv[])
   while(true)
   {
     // Test if we received a frame
-    if (nfc_target_receive_bits(pdi,abtRecv,&uiRecvBits,null))
+    if (nfc_target_receive_bits(pdi,abtRecv,&uiRecvBits,NULL))
     {
       // Prepare the command to send back for the anti-collision request
       switch(uiRecvBits)
@@ -102,7 +103,7 @@ int main(int argc, const char* argv[])
       if(uiTxBits)
       {
         // Send and print the command to the screen
-        nfc_target_send_bits(pdi,pbtTx,uiTxBits,null);
+        nfc_target_send_bits(pdi,pbtTx,uiTxBits,NULL);
         printf("T: ");
         print_hex_bits(pbtTx,uiTxBits);
       }
diff --git a/src/libnfc.c b/src/libnfc.c
index f83dcd6..c737449 100644
--- a/src/libnfc.c
+++ b/src/libnfc.c
@@ -19,10 +19,13 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "libnfc.h"
-#include "bitutils.h"
+
 #include <stdio.h>
+#include <stddef.h>
 #include <string.h>
 
+#include "bitutils.h"
+
 // Registers and symbols masks used to covers parts within a register
 #define REG_CIU_TX_MODE           0x6302
   #define SYMBOL_TX_CRC_ENABLE      0x80
@@ -120,13 +123,13 @@ bool pn53x_set_reg(const dev_info* pdi, uint16_t ui16Reg, uint8_t ui8SybmolMask,
   pncmd_set_register[2] = ui16Reg >> 8;
   pncmd_set_register[3] = ui16Reg & 0xff;
   pncmd_set_register[4] = ui8Value | (pn53x_get_reg(pdi,ui16Reg) & (~ui8SybmolMask));
-  return pdi->pdc->transceive(pdi->ds,pncmd_set_register,5,null,null);
+  return pdi->pdc->transceive(pdi->ds,pncmd_set_register,5,NULL,NULL);
 }
 
 bool pn53x_set_parameters(const dev_info* pdi, uint8_t ui8Value)
 {
   pncmd_set_parameters[2] = ui8Value;
-  return pdi->pdc->transceive(pdi->ds,pncmd_set_parameters,3,null,null);
+  return pdi->pdc->transceive(pdi->ds,pncmd_set_parameters,3,NULL,NULL);
 }
 
 bool pn53x_set_tx_bits(const dev_info* pdi, uint8_t ui8Bits)
@@ -233,7 +236,7 @@ bool pn53x_unwrap_frame(const byte* pbtFrame, const uint32_t uiFrameBits, byte*
       btFrame = mirror(pbtFramePos[uiDataPos+1]);
       btData |= (btFrame >> (8-uiBitPos));
       pbtRx[uiDataPos] = mirror(btData);
-      if(pbtRxPar != null) pbtRxPar[uiDataPos] = ((btFrame >> (7-uiBitPos)) & 0x01);
+      if(pbtRxPar != NULL) pbtRxPar[uiDataPos] = ((btFrame >> (7-uiBitPos)) & 0x01);
       // Increase the data (without parity bit) position
       uiDataPos++;
       // Test if we are done
@@ -263,7 +266,7 @@ dev_info* nfc_connect()
     {
       // Great we have claimed a device
 		  pdi->pdc = &(dev_callbacks_list[uiDev]);
-      pdi->pdc->transceive(pdi->ds,pncmd_get_register,4,null,null);
+      pdi->pdc->transceive(pdi->ds,pncmd_get_register,4,NULL,NULL);
 
       // Try to retrieve PN53x chip revision
       if (!pdi->pdc->transceive(pdi->ds,pncmd_get_firmware_version,2,abtFw,&uiFwLen))
@@ -332,7 +335,7 @@ bool nfc_configure(dev_info* pdi, const dev_config_option dco, const bool bEnabl
 
     case DCO_ACTIVATE_FIELD:
       pncmd_rf_configure_field[3] = (bEnable) ? 1 : 0;
-      if (!pdi->pdc->transceive(pdi->ds,pncmd_rf_configure_field,4,null,null)) return false;
+      if (!pdi->pdc->transceive(pdi->ds,pncmd_rf_configure_field,4,NULL,NULL)) return false;
     break;
 
     case DCO_ACTIVATE_CRYPTO1:
@@ -345,7 +348,7 @@ bool nfc_configure(dev_info* pdi, const dev_config_option dco, const bool bEnabl
       pncmd_rf_configure_retry_select[3] = (bEnable) ? 0xff : 0x00; // MxRtyATR, default: active = 0xff, passive = 0x02
       pncmd_rf_configure_retry_select[4] = (bEnable) ? 0xff : 0x00; // MxRtyPSL, default: 0x01
       pncmd_rf_configure_retry_select[5] = (bEnable) ? 0xff : 0x00; // MxRtyPassiveActivation, default: 0xff
-      if(!pdi->pdc->transceive(pdi->ds,pncmd_rf_configure_retry_select,6,null,null)) return false;
+      if(!pdi->pdc->transceive(pdi->ds,pncmd_rf_configure_retry_select,6,NULL,NULL)) return false;
     break;
 
     case DCO_ACCEPT_INVALID_FRAMES:
@@ -477,7 +480,7 @@ bool nfc_reader_select(const dev_info* pdi, const init_modulation im, const byte
 
 bool nfc_reader_deselect(const dev_info* pdi)
 {
-  return (pdi->pdc->transceive(pdi->ds,pncmd_reader_deselect,3,null,null));
+  return (pdi->pdc->transceive(pdi->ds,pncmd_reader_deselect,3,NULL,NULL));
 }
 
 bool nfc_reader_transceive_bits(const dev_info* pdi, const byte* pbtTx, const uint32_t uiTxBits, const byte* pbtTxPar, byte* pbtRx, uint32_t* puiRxBits, byte* pbtRxPar)
diff --git a/src/list.c b/src/list.c
index be02e9b..742cdc7 100644
--- a/src/list.c
+++ b/src/list.c
@@ -1,96 +1,99 @@
-/*
- 
-Public platform independent Near Field Communication (NFC) library
-Copyright (C) 2009, Roel Verdult
- 
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-*/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "libnfc.h"
-
-static dev_info* pdi;
-static byte abtFelica[5] = { 0x00, 0xff, 0xff, 0x00, 0x00 };
-
-int main(int argc, const char* argv[])
-{			
-  tag_info ti;
-
-  // Try to open the NFC reader
-  pdi = nfc_connect();
-  
-  if (pdi == INVALID_DEVICE_INFO)
-  {
-    printf("Error connecting NFC reader\n");
-    return 1;
-  }
-  nfc_reader_init(pdi);
-
+/*
+ 
+Public platform independent Near Field Communication (NFC) library
+Copyright (C) 2009, Roel Verdult
+ 
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+*/
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+
+#include <string.h>
+
+#include "libnfc.h"
+
+static dev_info* pdi;
+static byte abtFelica[5] = { 0x00, 0xff, 0xff, 0x00, 0x00 };
+
+int main(int argc, const char* argv[])
+{			
+  tag_info ti;
+
+  // Try to open the NFC reader
+  pdi = nfc_connect();
+  
+  if (pdi == INVALID_DEVICE_INFO)
+  {
+    printf("Error connecting NFC reader\n");
+    return 1;
+  }
+  nfc_reader_init(pdi);
+
   // Drop the field for a while
   nfc_configure(pdi,DCO_ACTIVATE_FIELD,false);
-
-  // Let the reader only try once to find a tag
-  nfc_configure(pdi,DCO_INFINITE_SELECT,false);
-
-  // Configure the CRC and Parity settings
-  nfc_configure(pdi,DCO_HANDLE_CRC,true);
-  nfc_configure(pdi,DCO_HANDLE_PARITY,true);
-
-  // Enable field so more power consuming cards can power themselves up
-  nfc_configure(pdi,DCO_ACTIVATE_FIELD,true);
-
-  printf("\nConnected to NFC reader: %s\n\n",pdi->acName);
-  
-  // Poll for a ISO14443A (MIFARE) tag
-  if (nfc_reader_select(pdi,IM_ISO14443A_106,null,null,&ti))
-  {
-    printf("The following (NFC) ISO14443A tag was found:\n\n");
-    printf("    ATQA (SENS_RES): "); print_hex(ti.tia.abtAtqa,2);
-    printf("       UID (NFCID%c): ",(ti.tia.abtUid[0]==0x08?'3':'1')); print_hex(ti.tia.abtUid,ti.tia.uiUidLen);
-    printf("      SAK (SEL_RES): "); print_hex(&ti.tia.btSak,1);
-    if (ti.tia.uiAtsLen)
-    {
-      printf("          ATS (ATR): ");
-      print_hex(ti.tia.abtAts,ti.tia.uiAtsLen);
-    }
-  }
-
-  // Poll for a Felica tag
-  if (nfc_reader_select(pdi,IM_FELICA_212,abtFelica,5,&ti) || nfc_reader_select(pdi,IM_FELICA_424,abtFelica,5,&ti))
-  {
-    printf("The following (NFC) Felica tag was found:\n\n");
-    printf("%18s","ID (NFCID2): "); print_hex(ti.tif.abtId,8);
-    printf("%18s","Parameter (PAD): "); print_hex(ti.tif.abtPad,8);
-  }
-
-  // Poll for a ISO14443B tag
-  if (nfc_reader_select(pdi,IM_ISO14443B_106,null,null,&ti))
-  {
-    // No test results yet
-    printf("iso14443b\n");
-  }
-
-  // Poll for a Jewel tag
-  if (nfc_reader_select(pdi,IM_JEWEL_106,null,null,&ti))
-  {
-    // No test results yet
-    printf("jewel\n");
-  }
-
-  nfc_disconnect(pdi);
-  return 1;
-}
+
+  // Let the reader only try once to find a tag
+  nfc_configure(pdi,DCO_INFINITE_SELECT,false);
+
+  // Configure the CRC and Parity settings
+  nfc_configure(pdi,DCO_HANDLE_CRC,true);
+  nfc_configure(pdi,DCO_HANDLE_PARITY,true);
+
+  // Enable field so more power consuming cards can power themselves up
+  nfc_configure(pdi,DCO_ACTIVATE_FIELD,true);
+
+  printf("\nConnected to NFC reader: %s\n\n",pdi->acName);
+  
+  // Poll for a ISO14443A (MIFARE) tag
+  if (nfc_reader_select(pdi,IM_ISO14443A_106,NULL,NULL,&ti))
+  {
+    printf("The following (NFC) ISO14443A tag was found:\n\n");
+    printf("    ATQA (SENS_RES): "); print_hex(ti.tia.abtAtqa,2);
+    printf("       UID (NFCID%c): ",(ti.tia.abtUid[0]==0x08?'3':'1')); print_hex(ti.tia.abtUid,ti.tia.uiUidLen);
+    printf("      SAK (SEL_RES): "); print_hex(&ti.tia.btSak,1);
+    if (ti.tia.uiAtsLen)
+    {
+      printf("          ATS (ATR): ");
+      print_hex(ti.tia.abtAts,ti.tia.uiAtsLen);
+    }
+  }
+
+  // Poll for a Felica tag
+  if (nfc_reader_select(pdi,IM_FELICA_212,abtFelica,5,&ti) || nfc_reader_select(pdi,IM_FELICA_424,abtFelica,5,&ti))
+  {
+    printf("The following (NFC) Felica tag was found:\n\n");
+    printf("%18s","ID (NFCID2): "); print_hex(ti.tif.abtId,8);
+    printf("%18s","Parameter (PAD): "); print_hex(ti.tif.abtPad,8);
+  }
+
+  // Poll for a ISO14443B tag
+  if (nfc_reader_select(pdi,IM_ISO14443B_106,NULL,NULL,&ti))
+  {
+    // No test results yet
+    printf("iso14443b\n");
+  }
+
+  // Poll for a Jewel tag
+  if (nfc_reader_select(pdi,IM_JEWEL_106,NULL,NULL,&ti))
+  {
+    // No test results yet
+    printf("jewel\n");
+  }
+
+  nfc_disconnect(pdi);
+  return 1;
+}
diff --git a/src/mftool.c b/src/mftool.c
index 39c2229..c52874d 100644
--- a/src/mftool.c
+++ b/src/mftool.c
@@ -21,6 +21,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <stddef.h>
+
 #include <string.h>
 #include <ctype.h>
 
@@ -72,7 +74,7 @@ bool read_card()
       {
         printf("x");
         // When a failure occured we need to redo the anti-collision
-        if (!nfc_reader_select(pdi,IM_ISO14443A_106,null,null,&ti))
+        if (!nfc_reader_select(pdi,IM_ISO14443A_106,NULL,NULL,&ti))
         {
           printf("!\nError: tag was removed\n");
           return 1;
@@ -155,7 +157,7 @@ bool write_card()
       {
         printf("x");
         // When a failure occured we need to redo the anti-collision
-        if (!nfc_reader_select(pdi,IM_ISO14443A_106,null,null,&ti))
+        if (!nfc_reader_select(pdi,IM_ISO14443A_106,NULL,NULL,&ti))
         {
           printf("!\nError: tag was removed\n");
           return false;
@@ -251,7 +253,7 @@ int main(int argc, const char* argv[])
   bUseKeyA = (tolower(*(argv[2])) == 'a');
 
   pfKeys = fopen(argv[3],"rb");
-  if (pfKeys == null)
+  if (pfKeys == NULL)
   {
     printf("Could not open file: %s\n",argv[3]);
     return 1;
@@ -270,7 +272,7 @@ int main(int argc, const char* argv[])
   } else {
     pfDump = fopen(argv[4],"rb");
 
-    if (pfDump == null)
+    if (pfDump == NULL)
     {
       printf("Could not open dump file: %s\n",argv[4]);
       return 1;
@@ -310,7 +312,7 @@ int main(int argc, const char* argv[])
   printf("Connected to NFC reader: %s\n",pdi->acName);
 
   // Try to find a MIFARE Classic tag
-  if (!nfc_reader_select(pdi,IM_ISO14443A_106,null,null,&ti))
+  if (!nfc_reader_select(pdi,IM_ISO14443A_106,NULL,NULL,&ti))
   {
     printf("Error: no tag was found\n");
     nfc_disconnect(pdi);
@@ -349,7 +351,7 @@ int main(int argc, const char* argv[])
       printf("Writing data to file: %s\n",argv[4]);
       fflush(stdout);
       pfDump = fopen(argv[4],"wb");
-      if (pfKeys == null)
+      if (pfKeys == NULL)
       {
         printf("Could not open file: %s\n",argv[4]);
         return 1;