diff --git a/src/misc/parseToPOD.cpp b/src/misc/parseToPOD.cpp
index 4ac3788..add8f21 100644
--- a/src/misc/parseToPOD.cpp
+++ b/src/misc/parseToPOD.cpp
@@ -308,7 +308,7 @@ noconvert:
     return 0;
 }
 
-#if defined(__vxworks)
+#if defined(vxWorks)
 /* vxworks version of std::istringstream >>uint64_t is buggy, we use out own implementation */
 static
 unsigned long long strtoull(const char *nptr, char **endptr, int base)
@@ -551,7 +551,7 @@ void parseToPOD(const string& in, float *out) {
 void parseToPOD(const string& in, double *out) {
     int err = epicsParseDouble(in.c_str(), out, NULL);
     if(err)   handleParseError(err);
-#if defined(__vxworks)
+#if defined(vxWorks)
     /* vxWorks strtod returns [-]epicsINF when it should return ERANGE error
      * if [-]epicsINF is returned and first char is a digit then translate this into ERANGE error
      */
diff --git a/src/misc/pv/sharedPtr.h b/src/misc/pv/sharedPtr.h
index 05bd3ca..b2d1007 100644
--- a/src/misc/pv/sharedPtr.h
+++ b/src/misc/pv/sharedPtr.h
@@ -26,7 +26,7 @@
 
 // where should we look?
 
-#if defined(__GNUC__) && __GNUC__>=4 && !defined(__vxworks)
+#if defined(__GNUC__) && __GNUC__>=4 && !defined(vxWorks)
    // GCC >=4.0.0
 #  define SHARED_FROM_TR1
 
diff --git a/src/pv/pvData.h b/src/pv/pvData.h
index 9cca66a..0f2605d 100644
--- a/src/pv/pvData.h
+++ b/src/pv/pvData.h
@@ -29,11 +29,11 @@
 #include <shareLib.h>
 #include <compilerDependencies.h>
 
-#if defined(__vxworks) && !defined(_WRS_VXWORKS_MAJOR)
+#if defined(vxWorks) && !defined(_WRS_VXWORKS_MAJOR)
 typedef class std::ios std::ios_base;
 #endif
 
-#if defined(__GNUC__) && !(defined(__vxworks) && !defined(_WRS_VXWORKS_MAJOR))
+#if defined(__GNUC__) && !(defined(vxWorks) && !defined(_WRS_VXWORKS_MAJOR))
 #define USAGE_DEPRECATED __attribute__((deprecated))
 #define USAGE_ERROR(MSG) __attribute__((error(MSG)))
 #else
diff --git a/src/pv/pvType.h b/src/pv/pvType.h
index 28ad878..fe2d1ab 100644
--- a/src/pv/pvType.h
+++ b/src/pv/pvType.h
@@ -27,7 +27,7 @@
 #include <string>
 #include <vector>
 
-#if defined(__vxworks) && \
+#if defined(vxWorks) && \
     (_WRS_VXWORKS_MAJOR+0 <= 6) && (_WRS_VXWORKS_MINOR+0 < 9)
 typedef int intptr_t;
 typedef unsigned int uintptr_t;