diff --git a/src/anticol.c b/src/anticol.c
index cf9a33e..0cc8494 100644
--- a/src/anticol.c
+++ b/src/anticol.c
@@ -94,7 +94,7 @@ bool transmit_bytes(const byte_t* pbtTx, const size_t szTxLen)
   return true;
 }
 
-void print_usage(void)
+void print_usage(char* argv[])
 {
   printf("Usage: %s [OPTIONS]\n", argv[0]);
   printf("Options:\n");
@@ -109,14 +109,14 @@ int main(int argc,char* argv[])
   // Get commandline options
   for (arg=1;arg<argc;arg++) {
     if (0 == strcmp(argv[arg], "-h")) {
-      print_usage();
+      print_usage(argv);
       return 0;
     } else if (0 == strcmp(argv[arg], "-q")) {
       INFO("Quiet mode.");
       quiet_output = true;
     } else {
       ERR("%s is not supported option.", argv[arg]);
-      print_usage();
+      print_usage(argv);
       return -1;
     }
   }
diff --git a/src/emulate.c b/src/emulate.c
index 40d9fc6..0dd17eb 100644
--- a/src/emulate.c
+++ b/src/emulate.c
@@ -36,7 +36,7 @@ byte_t abtAtqa      [2] = { 0x04,0x00 };
 byte_t abtUidBcc    [5] = { 0xDE,0xAD,0xBE,0xAF,0x62 };
 byte_t abtSak       [9] = { 0x08,0xb6,0xdd };
 
-void print_usage(void)
+void print_usage(char* argv[])
 {
   printf("Usage: %s [OPTIONS] [UID]\n", argv[0]);
   printf("Options:\n");
@@ -57,7 +57,7 @@ int main(int argc, char *argv[])
   // Get commandline options
   for (arg=1;arg<argc;arg++) {
     if (0 == strcmp(argv[arg], "-h")) {
-      print_usage();
+      print_usage(argv);
       return 0;
     } else if (0 == strcmp(argv[arg], "-q")) {
       INFO("Quiet mode.");
@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
       }
     } else {
       ERR("%s is not supported option.", argv[arg]);
-      print_usage();
+      print_usage(argv);
       return -1;
     }
   }
diff --git a/src/relay.c b/src/relay.c
index 457066e..2bfd218 100644
--- a/src/relay.c
+++ b/src/relay.c
@@ -35,7 +35,7 @@ static size_t szTagRxBits;
 static dev_info* pdiReader;
 static dev_info* pdiTag;
 
-void print_usage(void)
+void print_usage(char* argv[])
 {
   printf("Usage: %s [OPTIONS]\n", argv[0]);
   printf("Options:\n");
@@ -51,14 +51,14 @@ int main(int argc,char* argv[])
   // Get commandline options
   for (arg=1;arg<argc;arg++) {
     if (0 == strcmp(argv[arg], "-h")) {
-      print_usage();
+      print_usage(argv);
       return 0;
     } else if (0 == strcmp(argv[arg], "-q")) {
       INFO("Quiet mode.");
       quiet_output = true;
     } else {
       ERR("%s is not supported option.", argv[arg]);
-      print_usage();
+      print_usage(argv);
       return -1;
     }
   }