diff --git a/src/OpenMesh/Core/IO/SR_binary_spec.hh b/src/OpenMesh/Core/IO/SR_binary_spec.hh
index 25babb1f..25e2a1e6 100644
--- a/src/OpenMesh/Core/IO/SR_binary_spec.hh
+++ b/src/OpenMesh/Core/IO/SR_binary_spec.hh
@@ -120,6 +120,7 @@ SIMPLE_BINARY(bool);
 SIMPLE_BINARY(float);
 SIMPLE_BINARY(double);
 SIMPLE_BINARY(long double);
+SIMPLE_BINARY(char);
 
 SIMPLE_BINARY(int8_t);
 SIMPLE_BINARY(int16_t);
diff --git a/src/OpenMesh/Core/IO/SR_types.hh b/src/OpenMesh/Core/IO/SR_types.hh
index 1e524e8d..9628f59e 100644
--- a/src/OpenMesh/Core/IO/SR_types.hh
+++ b/src/OpenMesh/Core/IO/SR_types.hh
@@ -82,7 +82,7 @@ typedef unsigned char    uchar;
 typedef unsigned short   ushort;
 typedef unsigned long    ulong;
 
-typedef char           int8_t;  typedef unsigned char      uint8_t;
+typedef signed char    int8_t;  typedef unsigned char      uint8_t;
 typedef short          int16_t; typedef unsigned short     uint16_t;
 
 // Int should be 32 bit on all archs.