fixed warnings in MSVC x64 compilation
diff --git a/tests/test.c b/tests/test.c
index 1c34603..652c4b7 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -17,7 +17,7 @@
 	cs_opt_value opt_value;
 };
 
-static void print_string_hex(unsigned char *str, int len)
+static void print_string_hex(unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_arm.c b/tests/test_arm.c
index 82df431..a265860 100644
--- a/tests/test_arm.c
+++ b/tests/test_arm.c
@@ -18,7 +18,7 @@
 	int syntax;
 };
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_arm64.c b/tests/test_arm64.c
index fc203b8..f721ce8 100644
--- a/tests/test_arm64.c
+++ b/tests/test_arm64.c
@@ -17,7 +17,7 @@
 	char *comment;
 };
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_detail.c b/tests/test_detail.c
index 9b142c3..2893642 100644
--- a/tests/test_detail.c
+++ b/tests/test_detail.c
@@ -17,7 +17,7 @@
 	cs_opt_value opt_value;
 };
 
-static void print_string_hex(unsigned char *str, int len)
+static void print_string_hex(unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_mips.c b/tests/test_mips.c
index 076b6d1..19eb7ee 100644
--- a/tests/test_mips.c
+++ b/tests/test_mips.c
@@ -17,7 +17,7 @@
 
 static csh handle;
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_ppc.c b/tests/test_ppc.c
index f68ad7b..8748438 100644
--- a/tests/test_ppc.c
+++ b/tests/test_ppc.c
@@ -16,7 +16,7 @@
 
 static csh handle;
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_skipdata.c b/tests/test_skipdata.c
index 767cb05..6f46276 100644
--- a/tests/test_skipdata.c
+++ b/tests/test_skipdata.c
@@ -19,7 +19,7 @@
 	size_t skipdata;
 };
 
-static void print_string_hex(unsigned char *str, int len)
+static void print_string_hex(unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_sparc.c b/tests/test_sparc.c
index 1368cf2..5840b72 100644
--- a/tests/test_sparc.c
+++ b/tests/test_sparc.c
@@ -16,7 +16,7 @@
 
 static csh handle;
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_systemz.c b/tests/test_systemz.c
index 55cc7eb..9906360 100644
--- a/tests/test_systemz.c
+++ b/tests/test_systemz.c
@@ -16,7 +16,7 @@
 
 static csh handle;
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_x86.c b/tests/test_x86.c
index 96ffdc9..a56cbe7 100644
--- a/tests/test_x86.c
+++ b/tests/test_x86.c
@@ -19,7 +19,7 @@
 	cs_opt_value opt_value;
 };
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;
 
diff --git a/tests/test_xcore.c b/tests/test_xcore.c
index 8e77270..2b681d7 100644
--- a/tests/test_xcore.c
+++ b/tests/test_xcore.c
@@ -16,7 +16,7 @@
 
 static csh handle;
 
-static void print_string_hex(char *comment, unsigned char *str, int len)
+static void print_string_hex(char *comment, unsigned char *str, size_t len)
 {
 	unsigned char *c;