plan9fox/sys/man/2/fgetc

.TH FGETC 2
.SH NAME
fgetc, getc, getchar, fputc, putc, putchar, ungetc, fgets, gets, fputs, puts, fread, fwrite \- Stdio input and output
.SH SYNOPSIS
.B #include <u.h>
.br
.B #include <stdio.h>
.ta \w'\fLlong 'u
.PP
.B
int	fgetc(FILE *f)
.PP
.B
int	getc(FILE *f)
.PP
.B
int	getchar(void)
.PP
.B
int	fputc(int c, FILE *f)
.PP
.B
int	putc(int c, FILE *f)
.PP
.B
int	putchar(int c)
.PP
.B
int	ungetc(int c, FILE *f)
.PP
.B
char	*fgets(char *s, int n, FILE *f)
.PP
.B
char	*gets(char *s)
.PP
.B
int	fputs(char *s, FILE *f)
.PP
.B
int	puts(char *s)
.PP
.B
long	fread(void *ptr, long itemsize, long nitems, FILE *stream)
.PP
.B
long	fwrite(void *ptr, long itemsize, long nitems, FILE *stream)
.SH DESCRIPTION
The functions described here work on open Stdio streams (see
.IR fopen ).
.PP
.I Fgetc
returns as an
.B int
the next
.B unsigned
.B char
from input stream
.IR f .
If the stream is at end-of-file, the end-of-file indicator for the
stream is set and
.I fgetc
returns
.BR EOF .
If a read error occurs, the error indicator for the stream is set and
.I fgetc
returns
.BR EOF .
.I Getc
is like
.I fgetc
except that it is implemented as a macro.
.I Getchar
is like
.I getc
except that it always reads from
.BR stdin .
.PP
.I Ungetc
pushes character
.I c
back onto the input stream
.BR f .
The pushed-back character will be returned by subsequent reads in
the reverse order of their pushing.
A successful intervening
.IR fseek ,
.IR fsetpos ,
or
.I rewind
on
.I f
discards any pushed-back characters for
.IR f .
One character of push-back is guaranteed.
.I Ungetc
returns the character pushed back (converted to
.B unsigned
.BR char ),
or
.B EOF
if the operation fails.
A successful call to
.I ungetc
clears the end-of-file indicator for the stream.
The file position indicator for the stream after reading or discarding
all pushed-back characters is the same as it was before the
characters were pushed back.
.PP
.I Fputc
writes character
.I c
(converted to
.B unsigned
.BR char )
to output stream
.IR f
at the position indicated by the position indicator for the stream
and advances the indicator appropriately.
If the file cannot support positioning requests, or if the stream was
opened with append mode, the character is appended to the output stream.
.I Fputc
returns the character written or
.B EOF
if there was a write error.
.I Putc
is like
.IR fputc
but is implemented as a macro.
.I Putchar
is like
.I putc
except that it always writes to
.BR stdout .
.PP
All other input takes place as if characters were read by successive
calls to
.I fgetc
and all other output takes place as if characters were written by
successive calls to
.IR fputc .
.PP
.I Fgets
reads up to and including the next newline, but not past end-of-file
or more than
.IR n -1
characters, from stream
.I f
into array
.IR s .
A null character is written immediately after the last character read
into the array (if any characters are read at all).
.I Fgets
returns
.I s
if successful, otherwise a null pointer.
.I Gets
is similar to
.IR fgets
except that it always reads from
.B stdin
and it discards the terminating newline, if any.
.I Gets
does not check for overflow of the receiving array, so its use is deprecated.
.PP
.I Fputs
writes the string
.I s
to  stream
.IR f ,
returning
.B EOF
if a write error occurred, otherwise a nonnegative value.
The terminating null character is not written.
.I Puts
is the same, writing to
.BR stdout .
.PP
.I Fread
reads from the named input
.IR stream 
at most
.I nitems
of data of size
.I itemsize
and the type of
.I *ptr
into a block beginning at
.IR ptr .
It returns the number of items actually read.
.PP
.I Fwrite
appends to the named output
.I stream
at most
.I nitems
of data of size
.I itemsize
and the type of
.I *ptr
from a block beginning at
.IR ptr .
It returns the number of items actually written.
.SH SOURCE
.B /sys/src/libstdio
.SH "SEE ALSO"
.IR read (2), 
.IR fopen (2),
.IR bio (2)
.SH BUGS
Stdio does not handle
.SM UTF
or runes; use Bio instead.