[thirdparty/man-pages.git] / man3 / fgetc.3

.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.\" Modified Wed Jul 28 11:12:07 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified Fri Sep  8 15:48:13 1995 by Andries Brouwer (aeb@cwi.nl)
.TH FGETC 3  2017-09-15 "GNU" "Linux Programmer's Manual"
.SH NAME
fgetc, fgets, getc, getchar, ungetc \- input of characters and strings
.SH SYNOPSIS
.nf
.B #include <stdio.h>
.PP
.BI "int fgetc(FILE *" stream );
.PP
.BI "char *fgets(char *" "s" ", int " "size" ", FILE *" "stream" );
.PP
.BI "int getc(FILE *" stream );
.PP
.B "int getchar(void);"
.PP
.BI "int ungetc(int " c ", FILE *" stream );
.fi
.SH DESCRIPTION
.BR fgetc ()
reads the next character from
.I stream
and returns it as an
.I unsigned char
cast to an
.IR int ,
or
.B EOF
on end of file or error.
.PP
.BR getc ()
is equivalent to
.BR fgetc ()
except that it may be implemented as a macro which evaluates
.I stream
more than once.
.PP
.BR getchar ()
is equivalent to
.BI "getc(" stdin ) \fR.
.PP
.BR fgets ()
reads in at most one less than
.I size
characters from
.I stream
and stores them into the buffer pointed to by
.IR s .
Reading stops after an
.B EOF
or a newline.
If a newline is read, it is stored into the buffer.
A terminating null byte (\(aq\e0\(aq)
is stored after the last character in the buffer.
.PP
.BR ungetc ()
pushes
.I c
back to
.IR stream ,
cast to
.IR "unsigned char" ,
where it is available for subsequent read operations.
Pushed-back characters
will be returned in reverse order; only one pushback is guaranteed.
.PP
Calls to the functions described here can be mixed with each other and with
calls to other input functions from the
.I stdio
library for the same input stream.
.PP
For nonlocking counterparts, see
.BR unlocked_stdio (3).
.SH RETURN VALUE
.BR fgetc (),
.BR getc ()
and
.BR getchar ()
return the character read as an
.I unsigned char
cast to an
.I int
or
.B EOF
on end of file or error.
.PP
.BR fgets ()
returns
.I s
on success, and NULL
on error or when end of file occurs while no characters have been read.
.PP
.BR ungetc ()
returns
.I c
on success, or
.B EOF
on error.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbw25 lb lb
l l l.
Interface	Attribute	Value
T{
.BR fgetc (),
.BR fgets (),
.BR getc (),
.br
.BR getchar (),
.BR ungetc ()
T}	Thread safety	MT-Safe
.TE
.sp 1
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008, C89, C99.
.PP
It is not advisable to mix calls to input functions from the
.I stdio
library with low-level calls to
.BR read (2)
for the file descriptor associated with the input stream; the results
will be undefined and very probably not what you want.
.SH SEE ALSO
.BR read (2),
.BR write (2),
.BR ferror (3),
.BR fgetwc (3),
.BR fgetws (3),
.BR fopen (3),
.BR fread (3),
.BR fseek (3),
.BR getline (3),
.BR gets (3),
.BR getwchar (3),
.BR puts (3),
.BR scanf (3),
.BR ungetwc (3),
.BR unlocked_stdio (3),
.BR feature_test_macros (7)
Commit	Line	Data
beef2770 DM	1	.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
	2	.\"
	3	.\" %%%LICENSE_START(VERBATIM)
	4	.\" Permission is granted to make and distribute verbatim copies of this
	5	.\" manual provided the copyright notice and this permission notice are
	6	.\" preserved on all copies.
	7	.\"
	8	.\" Permission is granted to copy and distribute modified versions of this
	9	.\" manual under the conditions for verbatim copying, provided that the
	10	.\" entire resulting derived work is distributed under the terms of a
	11	.\" permission notice identical to this one.
	12	.\"
	13	.\" Since the Linux kernel and libraries are constantly changing, this
	14	.\" manual page may be incorrect or out-of-date. The author(s) assume no
	15	.\" responsibility for errors or omissions, or for damages resulting from
	16	.\" the use of the information contained herein. The author(s) may not
	17	.\" have taken the same level of care in the production of this manual,
	18	.\" which is licensed free of charge, as they might when working
	19	.\" professionally.
	20	.\"
	21	.\" Formatted or processed versions of this manual, if unaccompanied by
	22	.\" the source, must acknowledge the copyright and authors of this work.
	23	.\" %%%LICENSE_END
	24	.\"
	25	.\" Modified Wed Jul 28 11:12:07 1993 by Rik Faith (faith@cs.unc.edu)
	26	.\" Modified Fri Sep 8 15:48:13 1995 by Andries Brouwer (aeb@cwi.nl)
4b8c67d9	27	.TH FGETC 3 2017-09-15 "GNU" "Linux Programmer's Manual"
beef2770 DM	28	.SH NAME
	29	fgetc, fgets, getc, getchar, ungetc \- input of characters and strings
	30	.SH SYNOPSIS
	31	.nf
	32	.B #include <stdio.h>
68e4db0a	33	.PP
beef2770	34	.BI "int fgetc(FILE *" stream );
dbfe9c70	35	.PP
beef2770	36	.BI "char fgets(char " "s" ", int " "size" ", FILE *" "stream" );
dbfe9c70	37	.PP
beef2770	38	.BI "int getc(FILE *" stream );
dbfe9c70	39	.PP
beef2770	40	.B "int getchar(void);"
dbfe9c70	41	.PP
beef2770 DM	42	.BI "int ungetc(int " c ", FILE *" stream );
	43	.fi
	44	.SH DESCRIPTION
	45	.BR fgetc ()
	46	reads the next character from
	47	.I stream
	48	and returns it as an
	49	.I unsigned char
	50	cast to an
	51	.IR int ,
	52	or
	53	.B EOF
	54	on end of file or error.
	55	.PP
	56	.BR getc ()
	57	is equivalent to
	58	.BR fgetc ()
	59	except that it may be implemented as a macro which evaluates
	60	.I stream
	61	more than once.
	62	.PP
	63	.BR getchar ()
	64	is equivalent to
	65	.BI "getc(" stdin ) \fR.
	66	.PP
	67	.BR fgets ()
	68	reads in at most one less than
	69	.I size
	70	characters from
	71	.I stream
	72	and stores them into the buffer pointed to by
	73	.IR s .
	74	Reading stops after an
	75	.B EOF
	76	or a newline.
	77	If a newline is read, it is stored into the buffer.
	78	A terminating null byte (\(aq\e0\(aq)
	79	is stored after the last character in the buffer.
	80	.PP
	81	.BR ungetc ()
	82	pushes
	83	.I c
	84	back to
	85	.IR stream ,
	86	cast to
	87	.IR "unsigned char" ,
	88	where it is available for subsequent read operations.
	89	Pushed-back characters
	90	will be returned in reverse order; only one pushback is guaranteed.
	91	.PP
	92	Calls to the functions described here can be mixed with each other and with
	93	calls to other input functions from the
	94	.I stdio
	95	library for the same input stream.
	96	.PP
	97	For nonlocking counterparts, see
	98	.BR unlocked_stdio (3).
	99	.SH RETURN VALUE
	100	.BR fgetc (),
	101	.BR getc ()
	102	and
	103	.BR getchar ()
	104	return the character read as an
	105	.I unsigned char
106	cast to an
107	.I int
108	or
109	.B EOF
110	on end of file or error.
111	.PP
112	.BR fgets ()
113	returns
114	.I s
115	on success, and NULL
116	on error or when end of file occurs while no characters have been read.
117	.PP
118	.BR ungetc ()
119	returns
120	.I c
121	on success, or
122	.B EOF
123	on error.
c8ed841a MS	124	.SH ATTRIBUTES
	125	For an explanation of the terms used in this section, see
	126	.BR attributes (7).
	127	.TS
	128	allbox;
	129	lbw25 lb lb
	130	l l l.
	131	Interface Attribute Value
	132	T{
	133	.BR fgetc (),
	134	.BR fgets (),
	135	.BR getc (),
	136	.br
	137	.BR getchar (),
	138	.BR ungetc ()
	139	T} Thread safety MT-Safe
	140	.TE
847e0d88	141	.sp 1
beef2770	142	.SH CONFORMING TO
505b9d7a	143	POSIX.1-2001, POSIX.1-2008, C89, C99.
847e0d88	144	.PP
beef2770 DM	145	It is not advisable to mix calls to input functions from the
	146	.I stdio
	147	library with low-level calls to
	148	.BR read (2)
	149	for the file descriptor associated with the input stream; the results
	150	will be undefined and very probably not what you want.
	151	.SH SEE ALSO
	152	.BR read (2),
	153	.BR write (2),
	154	.BR ferror (3),
	155	.BR fgetwc (3),
	156	.BR fgetws (3),
	157	.BR fopen (3),
	158	.BR fread (3),
	159	.BR fseek (3),
	160	.BR getline (3),
d4df4e8a	161	.BR gets (3),
beef2770 DM	162	.BR getwchar (3),
beef2770 DM	163	.BR puts (3),
beef2770 DM	164	.BR scanf (3),
	165	.BR ungetwc (3),
	166	.BR unlocked_stdio (3),
	167	.BR feature_test_macros (7)