4.3BSD-UWisc/man/cat3/stdio.3s
STDIO(3S) UNIX Programmer's Manual STDIO(3S)
NAME
stdio - standard buffered input/output package
SYNOPSIS
#include <stdio.h>
FILE *stdin;
FILE *stdout;
FILE *stderr;
DESCRIPTION
The functions described in section 3S constitute a user-
level buffering scheme. The in-line macros _g_e_t_c and
_p_u_t_c(3S) handle characters quickly. The higher level rou-
tines _g_e_t_s, _f_g_e_t_s, _s_c_a_n_f, _f_s_c_a_n_f, _f_r_e_a_d, _p_u_t_s, _f_p_u_t_s,
_p_r_i_n_t_f, _f_p_r_i_n_t_f, _f_w_r_i_t_e all use _g_e_t_c and _p_u_t_c; they can be
freely intermixed.
A file with associated buffering is called a _s_t_r_e_a_m, and is
declared to be a pointer to a defined type FILE. _F_o_p_e_n(3S)
creates certain descriptive data for a stream and returns a
pointer to designate the stream in all further transactions.
There are three normally open streams with constant pointers
declared in the include file and associated with the stan-
dard open files:
stdin standard input file
stdout standard output file
stderr standard error file
A constant `pointer' NULL (0) designates no stream at all.
An integer constant EOF (-1) is returned upon end of file or
error by integer functions that deal with streams.
Any routine that uses the standard input/output package must
include the header file <_s_t_d_i_o._h> of pertinent macro defini-
tions. The functions and constants mentioned in sections
labeled 3S are declared in the include file and need no
further declaration. The constants, and the following
`functions' are implemented as macros; redeclaration of
these names is perilous: _g_e_t_c, _g_e_t_c_h_a_r, _p_u_t_c, _p_u_t_c_h_a_r, _f_e_o_f,
_f_e_r_r_o_r, _f_i_l_e_n_o.
SEE ALSO
open(2), close(2), read(2), write(2), fread(3S), fseek(3S),
f*(3S)
DIAGNOSTICS
The value EOF is returned uniformly to indicate that a FILE
pointer has not been initialized with _f_o_p_e_n, input (output)
has been attempted on an output (input) stream, or a FILE
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STDIO(3S) UNIX Programmer's Manual STDIO(3S)
pointer designates corrupt or otherwise unintelligible FILE
data.
For purposes of efficiency, this implementation of the stan-
dard library has been changed to line buffer output to a
terminal by default and attempts to do this transparently by
flushing the output whenever a _r_e_a_d(2) from the standard
input is necessary. This is almost always transparent, but
may cause confusion or malfunctioning of programs which use
standard i/o routines but use _r_e_a_d(2) themselves to read
from the standard input.
In cases where a large amount of computation is done after
printing part of a line on an output terminal, it is neces-
sary to _f_f_l_u_s_h(3S) the standard output before going off and
computing so that the output will appear.
BUGS
The standard buffered functions do not interact well with
certain other library and system functions, especially _v_f_o_r_k
and _a_b_o_r_t.
LIST OF FUNCTIONS
_N_a_m_e _A_p_p_e_a_r_s _o_n _P_a_g_e _D_e_s_c_r_i_p_t_i_o_n
9 clearerr ferror.3s stream status inquiries
fclose fclose.3s close or flush a stream
fdopen fopen.3s open a stream
feof ferror.3s stream status inquiries
ferror ferror.3s stream status inquiries
fflush fclose.3s close or flush a stream
fgetc getc.3s get character or word from stream
fgets gets.3s get a string from a stream
fileno ferror.3s stream status inquiries
fopen fopen.3s open a stream
fprintf printf.3s formatted output conversion
fputc putc.3s put character or word on a stream
fputs puts.3s put a string on a stream
fread fread.3s buffered binary input/output
freopen fopen.3s open a stream
fscanf scanf.3s formatted input conversion
fseek fseek.3s reposition a stream
ftell fseek.3s reposition a stream
fwrite fread.3s buffered binary input/output
getc getc.3s get character or word from stream
getchar getc.3s get character or word from stream
gets gets.3s get a string from a stream
getw getc.3s get character or word from stream
printf printf.3s formatted output conversion
putc putc.3s put character or word on a stream
putchar putc.3s put character or word on a stream
puts puts.3s put a string on a stream
putw putc.3s put character or word on a stream
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STDIO(3S) UNIX Programmer's Manual STDIO(3S)
rewind fseek.3s reposition a stream
scanf scanf.3s formatted input conversion
setbuf setbuf.3s assign buffering to a stream
setbuffer setbuf.3s assign buffering to a stream
setlinebuf setbuf.3s assign buffering to a stream
sprintf printf.3s formatted output conversion
sscanf scanf.3s formatted input conversion
ungetc ungetc.3s push character back into input stream
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