gets(3p) — Linux manual page

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

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.1‐2017 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(3p).

       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(3p), ferror(3p),
       fgets(3p)

       The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)

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(3P)

Pages that refer to this page: stdio.h(0p), fgetc(3p), fgets(3p), fread(3p), stdin(3p)

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