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Diffstat (limited to 'man/man3/gets.3')
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1 files changed, 107 insertions, 0 deletions
diff --git a/man/man3/gets.3 b/man/man3/gets.3 new file mode 100644 index 000000000..8ffffaaa6 --- /dev/null +++ b/man/man3/gets.3 @@ -0,0 +1,107 @@ +'\" t +.\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de) +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" Modified Wed Jul 28 11:12:07 1993 by Rik Faith (faith@cs.unc.edu) +.\" Modified Fri Sep 8 15:48:13 1995 by Andries Brouwer (aeb@cwi.nl) +.\" Modified 2013-12-31, David Malcolm <dmalcolm@redhat.com> +.\" Split gets(3) into its own page; fgetc() et al. move to fgetc(3) +.TH gets 3 (date) "Linux man-pages (unreleased)" +.SH NAME +gets \- get a string from standard input (DEPRECATED) +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdio.h> +.P +.BI "[[deprecated]] char *gets(char *" "s" ); +.fi +.SH DESCRIPTION +.IR "Never use this function" . +.P +.BR gets () +reads a line from +.I stdin +into the buffer pointed to by +.I s +until either a terminating newline or +.BR EOF , +which it replaces with a null byte (\[aq]\e0\[aq]). +No check for buffer overrun is performed (see BUGS below). +.SH RETURN VALUE +.BR gets () +returns +.I s +on success, and NULL +on error or when end of file occurs while no characters have been read. +However, given the lack of buffer overrun checking, there can be no +guarantees that the function will even return. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR gets () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +C89, POSIX.1-2001. +.P +LSB deprecates +.BR gets (). +POSIX.1-2008 marks +.BR gets () +obsolescent. +ISO C11 removes the specification of +.BR gets () +from the C language, and since glibc 2.16, +glibc header files don't expose the function declaration if the +.B _ISOC11_SOURCE +feature test macro is defined. +.SH BUGS +Never use +.BR gets (). +Because it is impossible to tell without knowing the data in advance how many +characters +.BR gets () +will read, and because +.BR gets () +will continue to store characters past the end of the buffer, +it is extremely dangerous to use. +It has been used to break computer security. +Use +.BR fgets () +instead. +.P +For more information, see CWE-242 (aka "Use of Inherently Dangerous +Function") at +http://cwe.mitre.org/data/definitions/242.html +.SH SEE ALSO +.BR read (2), +.BR write (2), +.BR ferror (3), +.BR fgetc (3), +.BR fgets (3), +.BR fgetwc (3), +.BR fgetws (3), +.BR fopen (3), +.BR fread (3), +.BR fseek (3), +.BR getline (3), +.BR getwchar (3), +.BR puts (3), +.BR scanf (3), +.BR ungetwc (3), +.BR unlocked_stdio (3), +.BR feature_test_macros (7) |