add directory Minix

Minix/1.7.5/MANUALS/CAT3/FOPEN.3

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+NAME
+	  fopen, freopen, fdopen - open	a stream
+SYNTAX
+	  #include <stdio.h>
+	  FILE *fopen (file-name, type)
+	  char *file-name, *type;
+	  FILE *freopen	(file-name, type, stream)
+	  char *file-name, *type;
+	  FILE *stream;
+	  FILE *fdopen (fildes,	type)
+	  int fildes;
+	  char *type;
+DESCRIPTION
+	  Fopen	opens the file named by	file-name and associates a
+	  stream with it.  Fopen returns a pointer to the FILE
+	  structure associated with the	stream.
+	  File-name points to a	character string that contains the
+	  name of the file to be opened.
+	  Type is a character string having one	of the following
+	  values:
+	       "r"	 open for reading
+	       "w"	 truncate or create for	writing
+	       "a"	 append; open for writing at end of file, or
+			 create	for writing
+	       "r+"	 open for update (reading and writing)
+	       "w+"	 truncate or create for	update
+	       "a+"	 append; open or create	for update at end-of-
+			 file
+	  Freopen substitutes the named	file in	place of the open
+	  stream.  The original	stream is closed, regardless of
+	  whether the open ultimately succeeds.	 Freopen returns a
+	  pointer to the FILE structure	associated with	stream.
+	  Freopen is typically used to attach the preopened streams
+	  associated with stdin, stdout	and stderr to other files.
+	  Fdopen associates a stream with a file descriptor.  File
+	  descriptors are obtained from	open, dup, creat, or pipe(2),
+				  
+	  which	open files but do not return pointers to a FILE
+	  structure stream. Streams are	necessary input	for many of
+	  the Section 3S library routines.  The	type of	stream must
+	  agree	with the mode of the open file.
+	  When a file is opened	for update, both input and output may
+	  be done on the resulting stream.  However, output may	not be
+	  directly followed by input without an	intervening fseek or
+	  rewind, and input may	not be directly	followed by output
+	  without an intervening fseek,	rewind,	or an input operation
+	  which	encounters end-of-file.
+	  When a file is opened	for append (i.e., when type is "a" or
+	  "a+"), it is impossible to overwrite information already in
+	  the file.  Fseek may be used to reposition the file pointer
+	  to any position in the file, but when	output is written to
+	  the file, the	current	file pointer is	disregarded.  All
+	  output is written at the end of the file and causes the file
+	  pointer to be	repositioned at	the end	of the output.	If two
+	  separate processes open the same file	for append, each
+	  process may write freely to the file without fear of
+	  destroying output being written by the other.	 The output
+	  from the two processes will be intermixed in the file	in the
+	  order	in which it is written.
+SEE ALSO
+	  creat(2), dup(2), open(2), pipe(2), fclose(3S), fseek(3S).
+DIAGNOSTICS
+	  Fopen	and freopen return a NULL pointer on failure.
+