4.4BSD/usr/share/man/cat3/stdio.0
STDIO(3) BSD Programmer's Manual STDIO(3)
NNAAMMEE
ssttddiioo - standard input/output library functions
SSYYNNOOPPSSIISS
##iinncclluuddee <<ssttddiioo..hh>>
FFIILLEE **ssttddiinn;;
FFIILLEE **ssttddoouutt;;
FFIILLEE **ssttddeerrrr;;
DDEESSCCRRIIPPTTIIOONN
The standard I/O library provides a simple and efficient buffered stream
I/O interface. Input and ouput 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 de-
vice) by _o_p_e_n_i_n_g 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 _f_i_l_e _p_o_s_i_t_i_o_n _i_n_d_i_c_a_t_o_r associated with the stream is
positioned at the start of the file (byte zero), unless the file is
opened with appened mode. If append mode is used, the position indicator
will be placed the end-of-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 ouput takes place as if all characters were read by successive calls
to the fputc(3) function.
A file is disassociated from a stream by _c_l_o_s_i_n_g the file. Ouput streams
are flushed (any unwritten buffer contents are transfered to the host en-
vironment) 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 exe-
cution, 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 out-
put 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 -- _s_t_a_n_d_a_r_d _i_n_p_u_t (for reading converntional input), --
_s_t_a_n_d_a_r_d _o_u_t_p_u_t (for writing converntional input), and _s_t_a_n_d_a_r_d _e_r_r_o_r
(for writing diagnostic output). These streams are abbreviated _s_t_d_i_n,
_s_t_d_o_u_t and _s_t_d_e_r_r. 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 ssttddiioo library is a part of the library libc and routines are automat-
ically 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 with-
out first removing their current definitions with #undef: BUFSIZ, EOF,
FILENAME_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.
SSEEEE AALLSSOO
open(2), close(2), read(2), write(2)
BBUUGGSS
The standard buffered functions do not interact well with certain other
library and system functions, especially vfork and abort.
SSTTAANNDDAARRDDSS
The ssttddiioo library conforms to ANSI C X3.159-1989 (``ANSI C '').
LLIISSTT OOFF FFUUNNCCTTIIOONNSS
FFuunnccttiioonn DDeessccrriippttiioonn
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
fgetline get a line from a stream
fgetpos reposition a stream
fgets get a line from a stream
fileno check and reset stream status
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
funopen open a stream
fwopen open 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
snprintf formatted output conversion
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
vsnprintf formatted output conversion
vsprintf formatted output conversion
vsscanf input format conversion
4th Berkeley Distribution June 4, 1993 3