7381dcc9ee
gets is unsafe and shouldn't be used (for many years now). Leave it in the existing symbol version so anything that previously linked aginst it still runs, but do not allow new software to link against it. (The compatability/legacy implementation must not be static so that the symbol and in particular the compat sym gets@FBSD_1.0 make it into libc.) PR: 222796 (exp-run) Reported by: Paul Vixie Reviewed by: allanjude, cy, eadler, gnn, jhb, kib, ngie (some earlier) Relnotes: Yes Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D12298
150 lines
3.8 KiB
Groff
150 lines
3.8 KiB
Groff
.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)fgets.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd September 1, 2019
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.Dt FGETS 3
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.Os
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.Sh NAME
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.Nm fgets ,
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.Nm gets_s
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.Nd get a line from a stream
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft char *
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.Fn fgets "char * restrict str" "int size" "FILE * restrict stream"
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.Ft char *
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.Fn gets_s "char *str" "rsize_t size"
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.Sh DESCRIPTION
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The
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.Fn fgets
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function
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reads at most one less than the number of characters specified by
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.Fa size
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from the given
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.Fa stream
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and stores them in the string
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.Fa str .
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Reading stops when a newline character is found,
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at end-of-file or error.
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The newline, if any, is retained.
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If any characters are read and there is no error, a
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.Ql \e0
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character is appended to end the string.
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.Pp
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The
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.Fn gets_s
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function
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is equivalent to
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.Fn fgets
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with a
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.Fa stream
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of
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.Dv stdin ,
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except that the newline character (if any) is not stored in the string.
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.Pp
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The
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.Fn gets
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function
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was unsafe and is no longer available.
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.Sh RETURN VALUES
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Upon successful completion,
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.Fn fgets
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and
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.Fn gets_s
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return
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a pointer to the string.
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If end-of-file occurs before any characters are read,
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they return
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.Dv NULL
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and the buffer contents remain unchanged.
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If an error occurs,
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they return
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.Dv NULL
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and the buffer contents are indeterminate.
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The
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.Fn fgets
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and
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.Fn gets_s
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functions
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do not distinguish between end-of-file and error, and callers must use
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.Xr feof 3
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and
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.Xr ferror 3
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to determine which occurred.
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EBADF
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The given
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.Fa stream
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is not a readable stream.
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.El
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.Pp
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The function
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.Fn fgets
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may also fail and set
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.Va errno
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for any of the errors specified for the routines
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.Xr fflush 3 ,
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.Xr fstat 2 ,
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.Xr read 2 ,
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or
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.Xr malloc 3 .
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.Pp
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The function
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.Fn gets_s
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may also fail and set
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.Va errno
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for any of the errors specified for the routine
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.Xr getchar 3 .
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.Sh SEE ALSO
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.Xr feof 3 ,
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.Xr ferror 3 ,
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.Xr fgetln 3 ,
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.Xr fgetws 3 ,
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.Xr getline 3
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.Sh STANDARDS
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The
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.Fn fgets
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function conforms to
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.St -isoC-99 .
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.Fn gets_s
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conforms to
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.St -isoC-2011
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K.3.7.4.1.
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.Fn gets
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has been removed from
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.St -isoC-2011 .
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