The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008, 2016 Edition
Copyright © 2001-2016 The IEEE and The Open Group

#### NAME

> gets - get a string from a stdin stream

#### SYNOPSIS

> ``[OB] #include <stdio.h>
> char *gets(char *`s`);``
> `
> `

#### DESCRIPTION

> [CX] 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.

> [CX] 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, [CX] 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

> Standard I/O Streams, feof, ferror, fgets

> XBD <stdio.h>

#### CHANGE HISTORY

> First released in Issue 1. Derived from Issue 1 of the SVID.

#### Issue 6

> Extensions beyond the ISO C standard are marked.

#### Issue 7

> Austin Group Interpretation 1003.1-2001 #051 is applied, clarifying the RETURN VALUE section.

> The gets() function is marked obsolescent.

> Changes are made related to support for finegrained timestamps.

> POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0257 [14] is applied.

End of informative text.

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