1STDIN(3P)                  POSIX Programmer's Manual                 STDIN(3P)
2
3
4

PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
10

NAME

12       stderr, stdin, stdout - standard I/O streams
13

SYNOPSIS

15       #include <stdio.h>
16
17       extern FILE *stderr, *stdin, *stdout;
18
19

DESCRIPTION

21       A file with associated buffering is called a stream and is declared  to
22       be  a pointer to a defined type FILE. The fopen() function shall create
23       certain descriptive data for a stream and return a pointer to designate
24       the  stream in all further transactions. Normally, there are three open
25       streams with constant pointers declared in  the  <stdio.h>  header  and
26       associated with the standard open files.
27
28       At  program start-up, three streams shall be predefined and need not be
29       opened explicitly: standard input  (for  reading  conventional  input),
30       standard  output  (for writing conventional output), and standard error
31       (for writing diagnostic output). When opened, the standard error stream
32       is  not  fully buffered; the standard input and standard output streams
33       are fully buffered if and only if the stream can be determined  not  to
34       refer to an interactive device.
35
36       The following symbolic values in <unistd.h> define the file descriptors
37       that shall be associated with the C-language stdin, stdout, and  stderr
38       when the application is started:
39
40       STDIN_FILENO
41              Standard input value, stdin. Its value is 0.
42
43       STDOUT_FILENO
44              Standard output value, stdout. Its value is 1.
45
46       STDERR_FILENO
47              Standard error value, stderr. Its value is 2.
48
49
50       The stderr stream is expected to be open for reading and writing.
51

RETURN VALUE

53       None.
54

ERRORS

56       No errors are defined.
57
58       The following sections are informative.
59

EXAMPLES

61       None.
62

APPLICATION USAGE

64       None.
65

RATIONALE

67       None.
68

FUTURE DIRECTIONS

70       None.
71

SEE ALSO

73       fclose(),   feof(),  ferror(),  fileno(),  fopen(),  fread(),  fseek(),
74       getc(), gets(), popen(), printf(),  putc(),  puts(),  read(),  scanf(),
75       setbuf(),  setvbuf(),  tmpfile(), ungetc(), vprintf(), the Base Defini‐
76       tions volume of IEEE Std 1003.1-2001, <stdio.h>, <unistd.h>
77

79       Portions of this text are reprinted and reproduced in  electronic  form
80       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
81       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
82       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
83       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
84       event of any discrepancy between this version and the original IEEE and
85       The Open Group Standard, the original IEEE and The Open Group  Standard
86       is  the  referee document. The original Standard can be obtained online
87       at http://www.opengroup.org/unix/online.html .
88
89
90
91IEEE/The Open Group                  2003                            STDIN(3P)
Impressum