1.\" $NetBSD: fgets.3,v 1.6 1997/01/17 02:38:19 perry Exp $ 2.\" 3.\" Copyright (c) 1990, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Chris Torek and the American National Standards Committee X3, 8.\" on Information Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. All advertising materials mentioning features or use of this software 19.\" must display the following acknowledgement: 20.\" This product includes software developed by the University of 21.\" California, Berkeley and its contributors. 22.\" 4. Neither the name of the University nor the names of its contributors 23.\" may be used to endorse or promote products derived from this software 24.\" without specific prior written permission. 25.\" 26.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36.\" SUCH DAMAGE. 37.\" 38.\" @(#)fgets.3 8.1 (Berkeley) 6/4/93 39.\" 40.Dd June 4, 1993 41.Dt FGETS 3 42.Os 43.Sh NAME 44.Nm fgets , 45.Nm gets 46.Nd get a line from a stream 47.Sh SYNOPSIS 48.Fd #include <stdio.h> 49.Ft char * 50.Fn fgets "char *str" "int size" "FILE *stream" 51.Ft char * 52.Fn gets "char *str" 53.Sh DESCRIPTION 54The 55.Fn fgets 56function 57reads at most one less than the number of characters specified by 58.Xr size 59from the given 60.Fa stream 61and stores them in the string 62.Fa str . 63Reading stops when a newline character is found, 64at end-of-file or error. 65The newline, if any, is retained. 66In any case a 67.Ql \e0 68character is appended to end the string. 69.Pp 70The 71.Fn gets 72function 73is equivalent to 74.Fn fgets 75with an infinite 76.Xr size 77and a 78.Fa stream 79of 80.Em stdin , 81except that the newline character (if any) is not stored in the string. 82It is the caller's responsibility to ensure that the input line, 83if any, is sufficiently short to fit in the string. 84.Sh RETURN VALUES 85.Pp 86Upon successful completion, 87.Fn fgets 88and 89.Fn gets 90return 91a pointer to the string. 92If end-of-file or an error occurs before any characters are read, 93they return 94.Dv NULL. 95The 96.Fn fgets 97and 98functions 99.Fn gets 100do not distinguish between end-of-file and error, and callers must use 101.Xr feof 3 102and 103.Xr ferror 3 104to determine which occurred. 105.Sh ERRORS 106.Bl -tag -width Er 107.It Bq Er EBADF 108The given 109.Fa stream 110is not a readable stream. 111.El 112.Pp 113The function 114.Fn fgets 115may also fail and set 116.Va errno 117for any of the errors specified for the routines 118.Xr fflush 3 , 119.Xr fstat 2 , 120.Xr read 2 , 121or 122.Xr malloc 3 . 123.Pp 124The function 125.Fn gets 126may also fail and set 127.Va errno 128for any of the errors specified for the routine 129.Xr getchar 3 . 130.Sh SEE ALSO 131.Xr feof 3 , 132.Xr ferror 3 , 133.Xr fgetln 3 134.Sh STANDARDS 135The functions 136.Fn fgets 137and 138.Fn gets 139conform to 140.St -ansiC . 141.Sh BUGS 142Since it is usually impossible to ensure that the next input line 143is less than some arbitrary length, and because overflowing the 144input buffer is almost invariably a security violation, programs 145should 146.Em NEVER 147use 148.Fn gets . 149The 150.Fn gets 151function 152exists purely to conform to 153.St -ansiC . 154