Originální popis anglicky:
stdio - standard input/output library functions
Návod, kniha: Linux Programmer's Manual
#include <stdio.h>
FILE *stdin;
FILE *stdout;
FILE *stderr;
The standard I/O library provides a simple and efficient buffered stream I/O
interface. Input and output is mapped into logical data streams and the
physical I/O characteristics are concealed. The functions and macros are
listed below; more information is available from the individual man pages.
A stream is associated with an external file (which may be a physical device) by
opening a file, which may involve creating a new file. Creating an
existing file causes its former contents to be discarded. If a file can
support positioning requests (such as a disk file, as opposed to a terminal)
then a
file position indicator associated with the stream is positioned
at the start of the file (byte zero), unless the file is opened with append
mode. If append mode is used, it is unspecified whether the position indicator
will be placed at the start or the end of the file. The position indicator is
maintained by subsequent reads, writes and positioning requests. All input
occurs as if the characters were read by successive calls to the
fgetc(3) function; all output takes place as if all characters were
written by successive calls to the
fputc(3) function.
A file is disassociated from a stream by
closing the file. Output streams
are flushed (any unwritten buffer contents are transferred to the host
environment) before the stream is disassociated from the file. The value of a
pointer to a
FILE object is indeterminate after a file is closed
(garbage).
A file may be subsequently reopened, by the same or another program execution,
and its contents reclaimed or modified (if it can be repositioned at the
start). If the main function returns to its original caller, or the
exit(3) function is called, all open files are closed (hence all output
streams are flushed) before program termination. Other methods of program
termination, such as
abort(3) do not bother about closing files
properly.
At program startup, three text streams are predefined and need not be opened
explicitly —
standard input (for reading conventional input),
—
standard output (for writing conventional input), and
standard error (for writing diagnostic output). These streams are
abbreviated
stdin,
stdout and
stderr. When opened, the
standard error stream is not fully buffered; the standard input and output
streams are fully buffered if and only if the streams do not to refer to an
interactive device.
Output streams that refer to terminal devices are always line buffered by
default; pending output to such streams is written automatically whenever an
input stream that refers to a terminal device is read. In cases where a large
amount of computation is done after printing part of a line on an output
terminal, it is necessary to
fflush(3) the standard output before going
off and computing so that the output will appear.
The
stdio library is a part of the library
libc and routines are
automatically loaded as needed by the compilers
cc(1) and
pc(1).
The
SYNOPSIS sections of the following manual pages indicate which
include files are to be used, what the compiler declaration for the function
looks like and which external variables are of interest.
The following are defined as macros; these names may not be re-used without
first removing their current definitions with
#undef:
BUFSIZ,
EOF,
FILENAME_MAX,
FOPEN_MAX,
L_cuserid,
L_ctermid,
L_tmpnam, NULL,
SEEK_END,
SEEK_SET,
SEE_CUR,
TMP_MAX,
clearerr,
feof,
ferror,
fileno,
fropen,
fwopen,
getc,
getchar,
putc,
putchar,
stderr,
stdin,
stdout. Function versions of the macro functions
feof,
ferror,
clearerr,
fileno,
getc,
getchar,
putc, and
putchar exist and will be used if the macros
definitions are explicitly removed.
- Function
- Description
- clearerr
- check and reset stream status
- fclose
- close a stream
- fdopen
- stream open functions
- feof
- check and reset stream status
- ferror
- check and reset stream status
- fflush
- flush a stream
- fgetc
- get next character or word from input stream
- fgetpos
- reposition a stream
- fgets
- get a line from a stream
- fileno
- return the integer descriptor of the argument stream
- fopen
- stream open functions
- fprintf
- formatted output conversion
- fpurge
- flush a stream
- fputc
- output a character or word to a stream
- fputs
- output a line to a stream
- fread
- binary stream input/output
- freopen
- stream open functions
- fropen
- open a stream
- fscanf
- input format conversion
- fseek
- reposition a stream
- fsetpos
- reposition a stream
- ftell
- reposition a stream
- fwrite
- binary stream input/output
- getc
- get next character or word from input stream
- getchar
- get next character or word from input stream
- gets
- get a line from a stream
- getw
- get next character or word from input stream
- mktemp
- make temporary file name (unique)
- perror
- system error messages
- printf
- formatted output conversion
- putc
- output a character or word to a stream
- putchar
- output a character or word to a stream
- puts
- output a line to a stream
- putw
- output a character or word to a stream
- remove
- remove directory entry
- rewind
- reposition a stream
- scanf
- input format conversion
- setbuf
- stream buffering operations
- setbuffer
- stream buffering operations
- setlinebuf
- stream buffering operations
- setvbuf
- stream buffering operations
- sprintf
- formatted output conversion
- sscanf
- input format conversion
- strerror
- system error messages
- sys_errlist
- system error messages
- sys_nerr
- system error messages
- tempnam
- temporary file routines
- tmpfile
- temporary file routines
- tmpnam
- temporary file routines
- ungetc
- un-get character from input stream
- vfprintf
- formatted output conversion
- vfscanf
- input format conversion
- vprintf
- formatted output conversion
- vscanf
- input format conversion
- vsprintf
- formatted output conversion
- vsscanf
- input format conversion
The
stdio library conforms to ANSI X3.159-1989 (``ANSI C'').
close(2),
open(2),
read(2),
write(2),
stdout(3)
