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PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface
may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface
may not be implemented on Linux.
NAME
gets — get a string from a stdin stream
SYNOPSIS
#include <stdio.h> char *gets(char *s);
DESCRIPTION
The functionality described on this reference page is aligned with the ISO C standard. Any conflict
between the requirements described here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The gets() function shall read bytes from the standard input stream, stdin, into the array pointed to by
s, until a <newline> is read or an end-of-file condition is encountered. Any <newline> shall be discarded
and a null byte shall be placed immediately after the last byte read into the array.
The gets() function may mark the last data access timestamp of the file associated with stream for
update. The last data access timestamp shall be marked for update by the first successful execution of
fgetc(), fgets(), fread(), fscanf(), getc(), getchar(), getdelim(), getline(), gets(), or scanf() using
stream that returns data not supplied by a prior call to ungetc().
RETURN VALUE
Upon successful completion, gets() shall return s. If the end-of-file indicator for the stream is set,
or if the stream is at end-of-file, the end-of-file indicator for the stream shall be set and gets()
shall return a null pointer. If a read error occurs, the error indicator for the stream shall be set,
gets() shall return a null pointer, and set errno to indicate the error.
ERRORS
Refer to fgetc().
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
Reading a line that overflows the array pointed to by s results in undefined behavior. The use of fgets()
is recommended.
Since the user cannot specify the length of the buffer passed to gets(), use of this function is
discouraged. The length of the string read is unlimited. It is possible to overflow this buffer in such a
way as to cause applications to fail, or possible system security violations.
Applications should use the fgets() function instead of the obsolescent gets() function.
RATIONALE
The standard developers decided to mark the gets() function as obsolescent even though it is in the ISO C
standard due to the possibility of buffer overflow.
FUTURE DIRECTIONS
The gets() function may be removed in a future version.
SEE ALSO
Section 2.5, Standard I/O Streams, feof(), ferror(), fgets()
The Base Definitions volume of POSIX.1‐2008, <stdio.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event
of any discrepancy between this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced
during the conversion of the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .