+/* Unlocked I/O
+ *
+ * Since threading was introduced in C11, FILE objects have had implicit locks
+ * to prevent data races and inconsistent output.
+ *
+ * PDCLib provides these functions from POSIX as an extension in order to enable
+ * users to access the underlying unlocked functions.
+ *
+ * For each function defined in C11 where an _unlocked variant is defined below,
+ * the behaviour of the _unlocked variant is the same except that it will not
+ * take the lock associated with the stream.
+ *
+ * flockfile, ftrylockfile and funlockfile can be used to manually manipulate
+ * the stream locks. The behaviour of the _unlocked functions if called when the
+ * stream isn't locked by the calling thread is implementation defined.
+ */
+#if _PDCLIB_POSIX_MIN(200112L) || _PDCLIB_BSD_SOURCE || _PDCLIB_SVID_SOURCE
+void flockfile(FILE *file);
+int ftrylockfile(FILE *file);
+void funlockfile(FILE *file);
+
+int getc_unlocked(FILE *stream);
+int getchar_unlocked(void);
+int putc_unlocked(int c, FILE *stream);
+int putchar_unlocked(int c);
+#endif
+
+#if _PDCLIB_BSD_SOURCE || _PDCLIB_SVID_SOURCE
+void clearerr_unlocked(FILE *stream);
+int feof_unlocked(FILE *stream);
+int ferror_unlocked(FILE *stream);
+int fileno_unlocked(FILE *stream);
+int fflush_unlocked(FILE *stream);
+int fgetc_unlocked(FILE *stream);
+int fputc_unlocked(int c, FILE *stream);
+size_t fread_unlocked(void *ptr, size_t size, size_t n, FILE *stream);
+size_t fwrite_unlocked(const void *ptr, size_t size, size_t n, FILE *stream);
+#endif
+
+#if _PDCLIB_GNU_SOURCE
+char *fgets_unlocked(char *s, int n, FILE *stream);
+int fputs_unlocked(const char *s, FILE *stream);
+#endif
+
+#if defined(_PDCLIB_EXTENSIONS)
+int fgetpos_unlocked( FILE * _PDCLIB_restrict stream, fpos_t * _PDCLIB_restrict pos ) _PDCLIB_nothrow;
+int fsetpos_unlocked( FILE * stream, const fpos_t * pos ) _PDCLIB_nothrow;
+long int ftell_unlocked( FILE * stream ) _PDCLIB_nothrow;
+int fseek_unlocked( FILE * stream, long int offset, int whence ) _PDCLIB_nothrow;
+
+int puts_unlocked( const char * s ) _PDCLIB_nothrow;
+int ungetc_unlocked( int c, FILE * stream ) _PDCLIB_nothrow;
+
+
+int printf_unlocked( const char * _PDCLIB_restrict format, ... ) _PDCLIB_nothrow;
+int vprintf_unlocked( const char * _PDCLIB_restrict format, _PDCLIB_va_list arg ) _PDCLIB_nothrow;
+int fprintf_unlocked( FILE * _PDCLIB_restrict stream, const char * _PDCLIB_restrict format, ... ) _PDCLIB_nothrow;
+int vfprintf_unlocked( FILE * _PDCLIB_restrict stream, const char * _PDCLIB_restrict format, _PDCLIB_va_list arg ) _PDCLIB_nothrow;
+int scanf_unlocked( const char * _PDCLIB_restrict format, ... ) _PDCLIB_nothrow;
+int vscanf_unlocked( const char * _PDCLIB_restrict format, _PDCLIB_va_list arg ) _PDCLIB_nothrow;
+int fscanf_unlocked( FILE * _PDCLIB_restrict stream, const char * _PDCLIB_restrict format, ... ) _PDCLIB_nothrow;
+int vfscanf_unlocked( FILE * _PDCLIB_restrict stream, const char * _PDCLIB_restrict format, _PDCLIB_va_list arg ) _PDCLIB_nothrow;
+
+
+// Todo: remove prefix?
+_PDCLIB_uint_fast64_t _PDCLIB_ftell64( FILE * stream ) _PDCLIB_nothrow;
+_PDCLIB_uint_fast64_t _PDCLIB_ftell64_unlocked( FILE * stream ) _PDCLIB_nothrow;
+#endif
+