1.\" $NetBSD: fgetln.3,v 1.3 1995/02/02 01:15:37 jtc Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)fgetln.3 8.3 (Berkeley) 4/19/94 35.\" 36.Dd April 19, 1994 37.Dt FGETLN 3 38.Os 39.Sh NAME 40.Nm fgetln 41.Nd get a line from a stream 42.Sh SYNOPSIS 43.Fd #include <stdio.h> 44.Ft char * 45.Fn fgetln "FILE *stream" "size_t *len" 46.Sh DESCRIPTION 47The 48.Fn fgetln 49function 50returns a pointer to the next line from the stream referenced by 51.Fa stream . 52This line is 53.Em not 54a C string as it does not end with a terminating 55.Dv NUL 56character. 57The length of the line, including the final newline, 58is stored in the memory location to which 59.Fa len 60points. 61(Note, however, that if the line is the last 62in a file that does not end in a newline, 63the returned text will not contain a newline.) 64.Sh RETURN VALUES 65Upon successful completion a pointer is returned; 66this pointer becomes invalid after the next 67.Tn I/O 68operation on 69.Fa stream 70(whether successful or not) 71or as soon as the stream is closed. 72Otherwise, 73.Dv NULL 74is returned. 75The 76.Fn fgetln 77function 78does not distinguish between end-of-file and error; the routines 79.Xr feof 3 80and 81.Xr ferror 3 82must be used 83to determine which occurred. 84If an error occurs, the global variable 85.Va errno 86is set to indicate the error. 87The end-of-file condition is remembered, even on a terminal, and all 88subsequent attempts to read will return 89.Dv NULL 90until the condition is 91cleared with 92.Xr clearerr 3 . 93.Pp 94The text to which the returned pointer points may be modified, 95provided that no changes are made beyond the returned size. 96These changes are lost as soon as the pointer becomes invalid. 97.Sh ERRORS 98.Bl -tag -width [EBADF] 99.It Bq Er EBADF 100The argument 101.Fa stream 102is not a stream open for reading. 103.El 104.Pp 105The 106.Fn fgetln 107function 108may also fail and set 109.Va errno 110for any of the errors specified for the routines 111.Xr fflush 3 , 112.Xr malloc 3 , 113.Xr read 2 , 114.Xr stat 2 , 115or 116.Xr realloc 3 . 117.Sh SEE ALSO 118.Xr ferror 3 , 119.Xr fgets 3 , 120.Xr fopen 3 , 121.Xr putc 3 122.Sh HISTORY 123The 124.Fn fgetln 125function first appeared in 4.4BSD. 126