diff --git a/.github/workflows/cd.yml b/.github/workflows/cd.yml
index 6135037..f8280b0 100644
--- a/.github/workflows/cd.yml
+++ b/.github/workflows/cd.yml
@@ -10,7 +10,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ windows-latest, macOS-latest ]
+        os: [ windows-latest, macOS-latest, ubuntu-latest ]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27c2c0e..7332221 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ windows-latest, macOS-latest ]
+        os: [ windows-latest, macOS-latest, ubuntu-latest ]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/src/cxx/fp_def.h b/src/cxx/fp_def.h
index 48a0f39..934ad3c 100644
--- a/src/cxx/fp_def.h
+++ b/src/cxx/fp_def.h
@@ -2,7 +2,7 @@
 #define FP_DEF_H
 
 #include "math.h"
-#ifndef __APPLE__
+#if !defined (__APPLE__) && !defined (__linux__)
 #include "mmsystem.h"
 #endif
 
@@ -47,7 +47,7 @@ typedef struct
 // extended wav format
 typedef struct
 {
-#ifndef __APPLE__
+#if !defined (__APPLE__) && !defined (__linux__)
     WAVEFORMATEX WaveFormatEx;
 #endif
     union
@@ -56,7 +56,7 @@ typedef struct
         {
             unsigned short wValidBitsPerSample;   // bits of precision
             unsigned long dwChannelMask;          // which channels are present in stream
-#ifndef __APPLE__
+#if !defined (__APPLE__) && !defined (__linux__)
             GUID SubFormat;
 #endif
         } stream;
@@ -83,4 +83,4 @@ typedef struct
 } TTimeSigInfo, *PTimeSigInfo;
 
 
-#endif   // FP_DEF_H
\ No newline at end of file
+#endif   // FP_DEF_H
diff --git a/src/cxx/fp_plugclass.cpp b/src/cxx/fp_plugclass.cpp
index df1b755..020ca51 100644
--- a/src/cxx/fp_plugclass.cpp
+++ b/src/cxx/fp_plugclass.cpp
@@ -3,8 +3,8 @@
 #endif
 #include "fp_plugclass.h"
 
-#ifdef __APPLE__
-#include <strings.h>
+#if defined (__APPLE__) || defined (__linux__)
+#include <string.h>
 #endif
 
 // destroy the object
diff --git a/src/cxx/fp_plugclass.h b/src/cxx/fp_plugclass.h
index 50f5e83..512599f 100644
--- a/src/cxx/fp_plugclass.h
+++ b/src/cxx/fp_plugclass.h
@@ -19,14 +19,14 @@ LockMix_Shared / UnlockMix_Shared
 #ifndef FP_PLUGCLASS_H
 #define FP_PLUGCLASS_H
 
-#ifdef __APPLE__
+#if defined (__APPLE__) || defined (__linux__) 
 #include <stdint.h>
 #else
 #include <objidl.h>
 #endif
 #include "fp_def.h"
 
-#ifdef __APPLE__
+#if defined (__APPLE__) || defined (__linux__)
 #define _stdcall
 #define __stdcall
 #define BOOL int
@@ -47,7 +47,7 @@ typedef long long LARGE_INTEGER;
 #pragma pack(4)
 
 
-#ifdef __APPLE__
+#if defined (__APPLE__) || defined (__linux__)
 #define STDMETHODCALLTYPE __stdcall
 class IStream
 {