1FOPEN(3S)                                                            FOPEN(3S)
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NAME

6       fopen, freopen, fdopen - open a stream
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SYNOPSIS

9       #include <stdio.h>
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11       FILE *fopen(filename, type)
12       char *filename, *type;
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14       FILE *freopen(filename, type, stream)
15       char *filename, *type;
16       FILE *stream;
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18       FILE *fdopen(fildes, type)
19       char *type;
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DESCRIPTION

22       Fopen opens the file named by filename and associates a stream with it.
23       Fopen returns a pointer to be used to identify the stream in subsequent
24       operations.
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26       Type is a character string having one of the following values:
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28       "r"  open for reading
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30       "w"  create for writing
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32       "a"  append: open for writing at end of file, or create for writing
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34       Freopen  substitutes  the  named  file in place of the open stream.  It
35       returns the original value of stream.  The original stream is closed.
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37       Freopen is typically used  to  attach  the  preopened  constant  names,
38       stdin, stdout, stderr, to specified files.
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40       Fdopen  associates  a stream with a file descriptor obtained from open,
41       dup, creat, or pipe(2).  The type of the stream  must  agree  with  the
42       mode of the open file.
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SEE ALSO

45       open(2), fclose(3)
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DIAGNOSTICS

48       Fopen  and  freopen  return  the  pointer  NULL  if  filename cannot be
49       accessed.
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BUGS

52       Fdopen is not portable to systems other than UNIX.
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56                                                                     FOPEN(3S)