--- src/assuan-handler.c
+++ src/assuan-handler.c
@@ -938,7 +938,7 @@
 #if defined(HAVE_W32CE_SYSTEM)
         fdarray[n++] = (void*)fileno (ctx->outbound.data.fp);
 #elif defined(HAVE_W32_SYSTEM)
-        fdarray[n++] = (void*)_get_osfhandle (fileno (ctx->outbound.data.fp));
+        fdarray[n++] = (void*)_get_osfhandle (_fileno (ctx->outbound.data.fp));
 #else
         fdarray[n++] = fileno (ctx->outbound.data.fp);
 #endif
--- src/assuan-logging.c
+++ src/assuan-logging.c
@@ -30,10 +30,15 @@
 # ifdef HAVE_WINSOCK2_H
 #  include <winsock2.h>
 # endif
+# include <process.h>
+# define getpid _getpid
 # include <windows.h>
 #endif /*HAVE_W32_SYSTEM*/
 #include <errno.h>
 #include <ctype.h>
+#if defined HAVE_W32_SYSTEM
+#define isascii __isascii
+#endif
 
 #include "assuan-defs.h"
 
--- src/assuan-pipe-connect.c
+++ src/assuan-pipe-connect.c
@@ -47,6 +47,8 @@
 # ifdef HAVE_WINSOCK2_H
 #  include <winsock2.h>
 # endif
+# include <process.h>
+# define getpid _getpid
 # include <windows.h>
 #endif
 
--- src/assuan-socket.c
+++ src/assuan-socket.c
@@ -27,6 +27,8 @@
 #include <stdlib.h>
 #ifdef HAVE_W32_SYSTEM
 # define WIN32_LEAN_AND_MEAN
+# include <process.h>
+# define getpid _getpid
 # include <windows.h>
 # include <wincrypt.h>
 #ifndef HAVE_W32CE_SYSTEM
--- src/conversion.c
+++ src/conversion.c
@@ -27,6 +27,9 @@
 #include <string.h>
 #include <errno.h>
 #include <ctype.h>
+#if defined HAVE_W32_SYSTEM
+#define isascii __isascii
+#endif
 
 #include "assuan-defs.h"
 #include "debug.h"
--- src/system-w32.c
+++ src/system-w32.c
@@ -453,7 +453,7 @@
 
   /* Dup stderr to /dev/null unless it is in the list of FDs to be
      passed to the child. */
-  fd = assuan_fd_from_posix_fd (fileno (stderr));
+  fd = assuan_fd_from_posix_fd (_fileno (stderr));
   fdp = fd_child_list;
   if (fdp)
     {