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.
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().
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.
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
Applications should use the fgets() function instead of the
obsolescent gets() function.
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
IEEE/The Open Group 2013 GETS(3P)