1.\" $NetBSD: fgets.3,v 1.9 1998/06/08 12:41:42 lukem 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 LIBRARY 48.Lb libc 49.Sh SYNOPSIS 50.Fd #include <stdio.h> 51.Ft char * 52.Fn fgets "char *str" "int size" "FILE *stream" 53.Ft char * 54.Fn gets "char *str" 55.Sh DESCRIPTION 56The 57.Fn fgets 58function 59reads at most one less than the number of characters specified by 60.Fa size 61from the given 62.Fa stream 63and stores them in the string 64.Fa str . 65Reading stops when a newline character is found, 66at end-of-file or error. 67The newline, if any, is retained. 68In any case a 69.Ql \e0 70character is appended to end the string. 71.Pp 72The 73.Fn gets 74function 75is equivalent to 76.Fn fgets 77with an infinite 78.Fa size 79and a 80.Fa stream 81of 82.Em stdin , 83except that the newline character (if any) is not stored in the string. 84It is the caller's responsibility to ensure that the input line, 85if any, is sufficiently short to fit in the string. 86.Sh RETURN VALUES 87.Pp 88Upon successful completion, 89.Fn fgets 90and 91.Fn gets 92return 93a pointer to the string. 94If end-of-file or an error occurs before any characters are read, 95they return 96.Dv NULL . 97The 98.Fn fgets 99and 100functions 101.Fn gets 102do not distinguish between end-of-file and error, and callers must use 103.Xr feof 3 104and 105.Xr ferror 3 106to determine which occurred. 107.Sh ERRORS 108.Bl -tag -width Er 109.It Bq Er EBADF 110The given 111.Fa stream 112is not a readable stream. 113.El 114.Pp 115The function 116.Fn fgets 117may also fail and set 118.Va errno 119for any of the errors specified for the routines 120.Xr fflush 3 , 121.Xr fstat 2 , 122.Xr read 2 , 123or 124.Xr malloc 3 . 125.Pp 126The function 127.Fn gets 128may also fail and set 129.Va errno 130for any of the errors specified for the routine 131.Xr getchar 3 . 132.Sh SEE ALSO 133.Xr feof 3 , 134.Xr ferror 3 , 135.Xr fgetln 3 136.Sh STANDARDS 137The functions 138.Fn fgets 139and 140.Fn gets 141conform to 142.St -ansiC . 143.Sh SECURITY CONSIDERATIONS 144Since it is usually impossible to ensure that the next input line 145is less than some arbitrary length, and because overflowing the 146input buffer is almost invariably a security violation, programs 147should 148.Em NEVER 149use 150.Fn gets . 151The 152.Fn gets 153function 154exists purely to conform to 155.St -ansiC . 156