+/* We can't define these using SCM_KEYWORD, because keywords have not
+ yet been initialized when scm_init_fports is called. */
+static SCM k_guess_encoding = SCM_UNDEFINED;
+static SCM k_encoding = SCM_UNDEFINED;
+
+SCM_DEFINE (scm_i_open_file, "open-file", 2, 0, 1,
+ (SCM filename, SCM mode, SCM keyword_args),
+ "Open the file whose name is @var{filename}, and return a port\n"
+ "representing that file. The attributes of the port are\n"
+ "determined by the @var{mode} string. The way in which this is\n"
+ "interpreted is similar to C stdio. The first character must be\n"
+ "one of the following:\n"
+ "@table @samp\n"
+ "@item r\n"
+ "Open an existing file for input.\n"
+ "@item w\n"
+ "Open a file for output, creating it if it doesn't already exist\n"
+ "or removing its contents if it does.\n"
+ "@item a\n"
+ "Open a file for output, creating it if it doesn't already\n"
+ "exist. All writes to the port will go to the end of the file.\n"
+ "The \"append mode\" can be turned off while the port is in use\n"
+ "@pxref{Ports and File Descriptors, fcntl}\n"
+ "@end table\n"
+ "The following additional characters can be appended:\n"
+ "@table @samp\n"
+ "@item b\n"
+ "Open the underlying file in binary mode, if supported by the system.\n"
+ "Also, open the file using the binary-compatible character encoding\n"
+ "\"ISO-8859-1\", ignoring the default port encoding.\n"
+ "@item +\n"
+ "Open the port for both input and output. E.g., @code{r+}: open\n"
+ "an existing file for both input and output.\n"
+ "@item 0\n"
+ "Create an \"unbuffered\" port. In this case input and output\n"
+ "operations are passed directly to the underlying port\n"
+ "implementation without additional buffering. This is likely to\n"
+ "slow down I/O operations. The buffering mode can be changed\n"
+ "while a port is in use @pxref{Ports and File Descriptors,\n"
+ "setvbuf}\n"
+ "@item l\n"
+ "Add line-buffering to the port. The port output buffer will be\n"
+ "automatically flushed whenever a newline character is written.\n"
+ "@end table\n"
+ "In theory we could create read/write ports which were buffered\n"
+ "in one direction only. However this isn't included in the\n"
+ "current interfaces. If a file cannot be opened with the access\n"
+ "requested, @code{open-file} throws an exception.")
+#define FUNC_NAME s_scm_i_open_file