[unix-history] / usr / src / lib / libc / stdio / fgetline.3

.\" Copyright (c) 1990, 1991 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)fgetline.3	5.4 (Berkeley) 4/19/91
.\"
.Dd April 19, 1991
.Dt FGETLINE 3
.Os
.Sh NAME
.Nm fgetline
.Nd get a line from a stream
.Sh SYNOPSIS
.Fd #include <stdio.h>
.Ft char *
.Fn fgetline "FILE *stream" "size_t *len"
.Sh DESCRIPTION
The
.Fn fgetline
function
returns a pointer to the next line from the stream referenced by
.Fa stream .
The newline character at the end of the line is replaced by a
.Dv NUL .
.Pp
If
.Fa len
is non-NULL, the length of the line, not counting the terminating
.Dv NUL ,
is stored in the memory location it references.
.Sh RETURN VALUES
Upon successful completion a pointer is returned;
this pointer becomes invalid after the next
.Tn I/O
operation on
.Fa stream
(whether successful or not)
or as soon as the stream is closed.
Otherwise,
.Dv NULL
is returned.
The
.Fn fgetline
function
does not distinguish between end-of-file and error; the routines
.Xr feof 3
and
.Xr ferror 3
must be used
to determine which occurred.
If an error occurrs, the global variable
.Va errno
is set to indicate the error.
The end-of-file condition is remembered, even on a terminal, and all
subsequent attempts to read will return
.Dv NULL
until the condition is
cleared with
.Xr clearerr 3 .
.Pp
The text to which the returned pointer points may be modified,
provided that no changes are made beyond the terminating
.Dv NUL .
These changes are lost as soon as the pointer becomes invalid.
.Sh ERRORS
.Bl -tag -width [EBADF]
.It Bq Er EBADF
The argument
.Fa stream
is not a stream open for reading.
.El
.Pp
The
.Fn fgetline
function
may also fail and set
.Va errno
for any of the errors specified for the routines
.Xr fflush 3 ,
.Xr malloc 3 ,
.Xr read 2 ,
.Xr stat 2 ,
or
.Xr realloc 3 .
.Sh SEE ALSO
.Xr ferror 3 ,
.Xr fgets 3 ,
.Xr fopen 3 ,
.Xr putc 3
.Sh HISTORY
The
.Fn fgetline
function is
.Ud .
.Sh BUGS
It is not possible to tell whether the final line of an input file
was terminated with a newline.
Commit	Line	Data
8d2f28ac WJ	1	.\" Copyright (c) 1990, 1991 The Regents of the University of California.
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)fgetline.3 5.4 (Berkeley) 4/19/91
	33	.\"
	34	.Dd April 19, 1991
	35	.Dt FGETLINE 3
	36	.Os
	37	.Sh NAME
	38	.Nm fgetline
	39	.Nd get a line from a stream
	40	.Sh SYNOPSIS
	41	.Fd #include <stdio.h>
	42	.Ft char *
	43	.Fn fgetline "FILE stream" "size_t len"
	44	.Sh DESCRIPTION
	45	The
	46	.Fn fgetline
	47	function
	48	returns a pointer to the next line from the stream referenced by
	49	.Fa stream .
	50	The newline character at the end of the line is replaced by a
	51	.Dv NUL .
	52	.Pp
	53	If
	54	.Fa len
	55	is non-NULL, the length of the line, not counting the terminating
	56	.Dv NUL ,
	57	is stored in the memory location it references.
	58	.Sh RETURN VALUES
	59	Upon successful completion a pointer is returned;
	60	this pointer becomes invalid after the next
	61	.Tn I/O
	62	operation on
	63	.Fa stream
	64	(whether successful or not)
65	or as soon as the stream is closed.
66	Otherwise,
67	.Dv NULL
68	is returned.
69	The
70	.Fn fgetline
71	function
72	does not distinguish between end-of-file and error; the routines
73	.Xr feof 3
74	and
75	.Xr ferror 3
76	must be used
77	to determine which occurred.
78	If an error occurrs, the global variable
79	.Va errno
80	is set to indicate the error.
81	The end-of-file condition is remembered, even on a terminal, and all
82	subsequent attempts to read will return
83	.Dv NULL
84	until the condition is
85	cleared with
86	.Xr clearerr 3 .
87	.Pp
88	The text to which the returned pointer points may be modified,
89	provided that no changes are made beyond the terminating
90	.Dv NUL .
91	These changes are lost as soon as the pointer becomes invalid.
92	.Sh ERRORS
93	.Bl -tag -width [EBADF]
94	.It Bq Er EBADF
95	The argument
96	.Fa stream
97	is not a stream open for reading.
98	.El
99	.Pp
100	The
101	.Fn fgetline
102	function
103	may also fail and set
104	.Va errno
105	for any of the errors specified for the routines
106	.Xr fflush 3 ,
107	.Xr malloc 3 ,
108	.Xr read 2 ,
109	.Xr stat 2 ,
110	or
111	.Xr realloc 3 .
112	.Sh SEE ALSO
113	.Xr ferror 3 ,
114	.Xr fgets 3 ,
115	.Xr fopen 3 ,
116	.Xr putc 3
117	.Sh HISTORY
118	The
119	.Fn fgetline
120	function is
121	.Ud .
122	.Sh BUGS
123	It is not possible to tell whether the final line of an input file
124	was terminated with a newline.