1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. 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.\" @(#)fgets.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: src/lib/libc/stdio/fgets.3,v 1.22 2009/02/28 06:00:58 das Exp $ 34.\" 35.Dd September 9, 2019 36.Dt GETS 3 37.Os 38.Sh NAME 39.Nm gets 40.Nd get a line from a stream 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In stdio.h 45.Ft char * 46.Fn gets "char *str" 47.Sh DESCRIPTION 48.Bf -symbolic 49This interface is made obsolete by 50.Xr fgets 3 51and 52.Xr gets_s 3 . 53See 54.Sx SECURITY CONSIDERATIONS 55below. 56.Ef 57.Pp 58The 59.Fn gets 60function 61is equivalent to 62.Xr fgets 3 63with an infinite 64.Fa size 65and a 66.Fa stream 67of 68.Dv stdin , 69except that the newline character (if any) is not stored in the string. 70It is the caller's responsibility to ensure that the input line, 71if any, is sufficiently short to fit in the string. 72.Sh RETURN VALUES 73Upon successful completion, 74.Fn gets 75returns 76a pointer to the string. 77If end-of-file occurs before any characters are read, 78they return 79.Dv NULL 80and the buffer contents remain unchanged. 81If an error occurs, 82they return 83.Dv NULL 84and the buffer contents are indeterminate. 85The 86.Fn gets 87function 88does not distinguish between end-of-file and error, and callers must use 89.Xr feof 3 90and 91.Xr ferror 3 92to determine which occurred. 93.Sh ERRORS 94.Bl -tag -width Er 95.It Bq Er EBADF 96The given 97.Fa stream 98is not a readable stream. 99.El 100.Pp 101The 102.Fn gets 103function may also fail and set 104.Va errno 105for any of the errors specified for the routine 106.Xr getchar 3 . 107.Sh SECURITY CONSIDERATIONS 108The 109.Fn gets 110function cannot be used securely. 111Because of its lack of bounds checking, 112and the inability for the calling program 113to reliably determine the length of the next incoming line, 114the use of this function enables malicious users 115to arbitrarily change a running program's functionality through 116a buffer overflow attack. 117It is strongly suggested that the 118.Fn fgets 119and 120.Fn gets_s 121functions be used in all cases. 122.Sh SEE ALSO 123.Xr fgets 3 , 124.Xr gets_s 3 125.Sh STANDARDS 126The 127.Fn gets 128function conforms to 129.St -isoC-99 . 130