GETS(3)                    POSIX Programmer's Manual                   GETS(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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.1-2017
       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.1-2017, <stdio.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  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.opengroup.org/unix/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 .



IEEE/The Open Group                  2017                              GETS(3)
