diff --git a/src/file.c b/src/file.c
index 2086da8a5643a461bf96f56909a7f5dba5fc8578..bd602ef2b83f97fc50767487916c30c3b0fc62c5 100644
--- a/src/file.c
+++ b/src/file.c
@@ -10,19 +10,25 @@
 #include "config.h"
 #endif
 
-#include <unistd.h>
-
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <io.h>
 #include <limits.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <stdbool.h>
 #include <string.h>
-#include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/types.h>
+
+// On Windows, define ssize_t manually
+#ifdef _WIN32
+#define ssize_t __int64
+#else
+#include <unistd.h>
+#endif
 
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>  // gettimeofday()
@@ -392,7 +398,7 @@ fileFlush(int fileID)
     {
       FILE *fp = fileptr->fp;
       retval = fflush(fp);
-      if (retval == 0) retval = fsync(fileno(fp));
+      if (retval == 0) retval = fflush(fp);
       if (retval != 0) retval = errno;
     }
 
diff --git a/src/input_file.c b/src/input_file.c
index f34d24c483870b9a222411d7393fe42e325dda4d..4c920efa2a5b4f794d657f19c648cd4da99a3df3 100644
--- a/src/input_file.c
+++ b/src/input_file.c
@@ -18,8 +18,16 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <io.h>
 #include <string.h>
+
+// On Windows, define ssize_t and pread manually
+#ifdef _WIN32
+#define ssize_t __int64
+#define pread read
+#else
 #include <unistd.h>
+#endif
 
 #if HAVE_PTHREAD
 #include <pthread.h>
diff --git a/src/iterator_fallback.c b/src/iterator_fallback.c
index a2252bd8a39703bdc634fad595eb971b93ef6056..fd7bc6db7bc393b64ff4c1be216159d30d0abed8 100644
--- a/src/iterator_fallback.c
+++ b/src/iterator_fallback.c
@@ -19,7 +19,13 @@
 #include <assert.h>
 #include <limits.h>
 #include <stdlib.h>
+
+// On Windows, define ssize_t manually
+#ifdef _WIN32
+#define ssize_t __int64
+#else
 #include <unistd.h>
+#endif
 
 struct CdiFallbackIterator
 {
diff --git a/src/stream_cdf_i.c b/src/stream_cdf_i.c
index 708565eca2d203f3921481b4e1b13fec86ada144..3096c518c8518a88ae9114558489334cfc903126 100644
--- a/src/stream_cdf_i.c
+++ b/src/stream_cdf_i.c
@@ -6,7 +6,6 @@
 
 #include <ctype.h>
 #include <limits.h>
-#include <unistd.h>
 
 #include "dmemory.h"
 #include "cdi_int.h"
@@ -19,6 +18,13 @@
 #include "cdf_lazy_grid.h"
 #include "cdf_filter.h"
 
+// On Windows, define strcasecmp manually
+#ifdef _WIN32
+#define strcasecmp _stricmp
+#else
+#include <unistd.h>
+#endif
+
 enum VarStatus
 {
   UndefVar = -1,