1STDIN(P)                   POSIX Programmer's Manual                  STDIN(P)
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NAME

6       stderr, stdin, stdout - standard I/O streams
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SYNOPSIS

9       #include <stdio.h>
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11       extern FILE *stderr, *stdin, *stdout;
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DESCRIPTION

15       A  file with associated buffering is called a stream and is declared to
16       be a pointer to a defined type FILE. The fopen() function shall  create
17       certain descriptive data for a stream and return a pointer to designate
18       the stream in all further transactions. Normally, there are three  open
19       streams  with  constant  pointers  declared in the <stdio.h> header and
20       associated with the standard open files.
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22       At program start-up, three streams shall be predefined and need not  be
23       opened  explicitly:  standard  input  (for reading conventional input),
24       standard output (for writing conventional output), and  standard  error
25       (for writing diagnostic output). When opened, the standard error stream
26       is not fully buffered; the standard input and standard  output  streams
27       are  fully  buffered if and only if the stream can be determined not to
28       refer to an interactive device.
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30       The following symbolic values in <unistd.h> define the file descriptors
31       that  shall be associated with the C-language stdin, stdout, and stderr
32       when the application is started:
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34       STDIN_FILENO
35              Standard input value, stdin. Its value is 0.
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37       STDOUT_FILENO
38              Standard output value, stdout. Its value is 1.
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40       STDERR_FILENO
41              Standard error value, stderr. Its value is 2.
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44       The stderr stream is expected to be open for reading and writing.
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RETURN VALUE

47       None.
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ERRORS

50       No errors are defined.
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52       The following sections are informative.
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EXAMPLES

55       None.
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APPLICATION USAGE

58       None.
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RATIONALE

61       None.
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FUTURE DIRECTIONS

64       None.
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SEE ALSO

67       fclose() , feof() , ferror() , fileno() , fopen() , fread() , fseek() ,
68       getc()  ,  gets()  ,  popen()  ,  printf() , putc() , puts() , read() ,
69       scanf() , setbuf() , setvbuf() , tmpfile() , ungetc() , vprintf() , the
70       Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>, <unistd.h>
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73       Portions  of  this text are reprinted and reproduced in electronic form
74       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
75       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
76       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
77       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
78       event of any discrepancy between this version and the original IEEE and
79       The  Open Group Standard, the original IEEE and The Open Group Standard
80       is the referee document. The original Standard can be  obtained  online
81       at http://www.opengroup.org/unix/online.html .
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85IEEE/The Open Group                  2003                             STDIN(P)
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