+#endif /* USE_SFIO */
+#endif /* PERLIO_IS_STDIO */
+
+#ifndef PerlIO
+/* ----------- PerlIO implementation ---------- */
+/* PerlIO not #define-d to something else - define the implementation */
+
+typedef struct _PerlIO PerlIOl;
+typedef struct _PerlIO_funcs PerlIO_funcs;
+typedef PerlIOl *PerlIO;
+#define PerlIO PerlIO
+#define PERLIO_LAYERS 1
+
+/* Making the big PerlIO_funcs vtables const is good (enables placing
+ * them in the const section which is good for speed, security, and
+ * embeddability) but this cannot be done by default because of
+ * backward compatibility. */
+#ifdef PERLIO_FUNCS_CONST
+#define PERLIO_FUNCS_DECL(funcs) const PerlIO_funcs funcs
+#define PERLIO_FUNCS_CAST(funcs) (PerlIO_funcs*)(funcs)
+#else
+#define PERLIO_FUNCS_DECL(funcs) PerlIO_funcs funcs
+#define PERLIO_FUNCS_CAST(funcs) (funcs)
+#endif
+
+PERL_EXPORT_C void PerlIO_define_layer(pTHX_ PerlIO_funcs *tab);
+PERL_EXPORT_C PerlIO_funcs *PerlIO_find_layer(pTHX_ const char *name,
+ STRLEN len,
+ int load);
+PERL_EXPORT_C PerlIO *PerlIO_push(pTHX_ PerlIO *f, PERLIO_FUNCS_DECL(*tab),
+ const char *mode, SV *arg);
+PERL_EXPORT_C void PerlIO_pop(pTHX_ PerlIO *f);
+PERL_EXPORT_C AV* PerlIO_get_layers(pTHX_ PerlIO *f);
+PERL_EXPORT_C void PerlIO_clone(pTHX_ PerlInterpreter *proto,
+ CLONE_PARAMS *param);
+
+#endif /* PerlIO */
+
+/* ----------- End of implementation choices ---------- */
+
+#ifndef PERLIO_IS_STDIO
+/* Not using stdio _directly_ as PerlIO */
+
+/* We now need to determine what happens if source trys to use stdio.
+ * There are three cases based on PERLIO_NOT_STDIO which XS code
+ * can set how it wants.
+ */
+
+#ifdef PERL_CORE
+/* Make a choice for perl core code
+ - currently this is set to try and catch lingering raw stdio calls.
+ This is a known issue with some non UNIX ports which still use
+ "native" stdio features.
+*/
+#ifndef PERLIO_NOT_STDIO
+#define PERLIO_NOT_STDIO 1
+#endif
+#else
+#ifndef PERLIO_NOT_STDIO
+#define PERLIO_NOT_STDIO 0
+#endif
+#endif
+
+#ifdef PERLIO_NOT_STDIO
+#if PERLIO_NOT_STDIO
+/*
+ * PERLIO_NOT_STDIO #define'd as 1
+ * Case 1: Strong denial of stdio - make all stdio calls (we can think of) errors
+ */
+#include "nostdio.h"
+#else /* if PERLIO_NOT_STDIO */
+/*
+ * PERLIO_NOT_STDIO #define'd as 0
+ * Case 2: Declares that both PerlIO and stdio can be used
+ */
+#endif /* if PERLIO_NOT_STDIO */
+#else /* ifdef PERLIO_NOT_STDIO */
+/*
+ * PERLIO_NOT_STDIO not defined
+ * Case 3: Try and fake stdio calls as PerlIO calls
+ */
+#include "fakesdio.h"
+#endif /* ifndef PERLIO_NOT_STDIO */
+#endif /* PERLIO_IS_STDIO */
+
+/* ----------- fill in things that have not got #define'd ---------- */
+
+#ifndef Fpos_t
+#define Fpos_t Off_t
+#endif