term% cat index.txt FGETC(2) System Calls Manual FGETC(2)
NAME
fgetc, getc, getchar, fputc, putc, putchar, ungetc, fgets, gets, fputs,
puts, fread, fwrite - Stdio input and output
SYNOPSIS
#include <u.h>
#include <stdio.h>
int fgetc(FILE *f)
int getc(FILE *f)
int getchar(void)
int fputc(int c, FILE *f)
int putc(int c, FILE *f)
int putchar(int c)
int ungetc(int c, FILE *f)
char *fgets(char *s, int n, FILE *f)
char *gets(char *s)
int fputs(char *s, FILE *f)
int puts(char *s)
long fread(void *ptr, long itemsize, long nitems, FILE *stream)
long fwrite(void *ptr, long itemsize, long nitems, FILE *stream)
DESCRIPTION
The functions described here work on open Stdio streams (see fopen).
Fgetc returns as an int the next unsigned char from input stream f. If
the stream is at end-of-file, the end-of-file indicator for the stream
is set and fgetc returns EOF. If a read error occurs, the error indi‐
cator for the stream is set and fgetc returns EOF. Getc is like fgetc
except that it is implemented as a macro. Getchar is like getc except
that it always reads from stdin.
Ungetc pushes character c back onto the input stream f. The pushed-
back character will be returned by subsequent reads in the reverse or‐
der of their pushing. A successful intervening fseek, fsetpos, or
rewind on f discards any pushed-back characters for f. One character
of push-back is guaranteed. Ungetc returns the character pushed back
(converted to unsigned char), or EOF if the operation fails. A suc‐
cessful call to 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.
Fputc writes character c (converted to unsigned char) to output stream
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. Fputc returns the charac‐
ter written or EOF if there was a write error. Putc is like fputc but
is implemented as a macro. Putchar is like putc except that it always
writes to stdout.
All other input takes place as if characters were read by successive
calls to fgetc and all other output takes place as if characters were
written by successive calls to fputc.
Fgets reads up to and including the next newline, but not past end-of-
file or more than n-1 characters, from stream f into array s. A null
character is written immediately after the last character read into the
array (if any characters are read at all). Fgets returns s if success‐
ful, otherwise a null pointer. Gets is similar to fgets except that it
always reads from stdin and it discards the terminating newline, if
any. Gets does not check for overflow of the receiving array, so its
use is deprecated.
Fputs writes the string s to stream f, returning EOF if a write error
occurred, otherwise a nonnegative value. The terminating null charac‐
ter is not written. Puts is the same, writing to stdout.
Fread reads from the named input stream at most nitems of data of size
itemsize and the type of *ptr into a block beginning at ptr. It re‐
turns the number of items actually read.
Fwrite appends to the named output stream at most nitems of data of
size itemsize and the type of *ptr from a block beginning at ptr. It
returns the number of items actually written.
SOURCE
/sys/src/libstdio
SEE ALSO
read(2), fopen(2), bio(2)
BUGS
Stdio does not handle UTF or runes; use Bio instead.
FGETC(2)