1GETS(3P) POSIX Programmer's Manual GETS(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 gets — get a string from a stdin stream
13
15 #include <stdio.h>
16 char *gets(char *s);
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20 The functionality described on this reference page is aligned with the
21 ISO C standard. Any conflict between the requirements described here
22 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
23 defers to the ISO C standard.
24 The gets() function shall read bytes from the standard input stream,
26 stdin, into the array pointed to by s, until a <newline> is read or an
27 end-of-file condition is encountered. Any <newline> shall be discarded
28 and a null byte shall be placed immediately after the last byte read
29 into the array.
30 The gets() function may mark the last data access timestamp of the file
32 associated with stream for update. The last data access timestamp shall
33 be marked for update by the first successful execution of fgetc(),
34 fgets(), fread(), fscanf(), getc(), getchar(), getdelim(), getline(),
35 gets(), or scanf() using stream that returns data not supplied by a
36 prior call to ungetc().
37
39 Upon successful completion, gets() shall return s. If the end-of-file
40 indicator for the stream is set, or if the stream is at end-of-file,
41 the end-of-file indicator for the stream shall be set and gets() shall
42 return a null pointer. If a read error occurs, the error indicator for
43 the stream shall be set, gets() shall return a null pointer, and set
44 errno to indicate the error.
45
47 Refer to fgetc().
48 The following sections are informative.
50
52 None.
53
55 Reading a line that overflows the array pointed to by s results in
56 undefined behavior. The use of fgets() is recommended.
57 Since the user cannot specify the length of the buffer passed to
59 gets(), use of this function is discouraged. The length of the string
60 read is unlimited. It is possible to overflow this buffer in such a way
61 as to cause applications to fail, or possible system security viola‐
62 tions.
63 Applications should use the fgets() function instead of the obsolescent
65 gets() function.
66
68 The standard developers decided to mark the gets() function as obsoles‐
69 cent even though it is in the ISO C standard due to the possibility of
70 buffer overflow.
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73 The gets() function may be removed in a future version.
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76 Section 2.5, Standard I/O Streams, feof(), ferror(), fgets()
77 The Base Definitions volume of POSIX.1‐2017, <stdio.h>
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81 Portions of this text are reprinted and reproduced in electronic form
82 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
83 table Operating System Interface (POSIX), The Open Group Base Specifi‐
84 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
85 Electrical and Electronics Engineers, Inc and The Open Group. In the
86 event of any discrepancy between this version and the original IEEE and
87 The Open Group Standard, the original IEEE and The Open Group Standard
88 is the referee document. The original Standard can be obtained online
89 at http://www.opengroup.org/unix/online.html .
90 Any typographical or formatting errors that appear in this page are
92 most likely to have been introduced during the conversion of the source
93 files to man page format. To report such errors, see https://www.ker‐
94 nel.org/doc/man-pages/reporting_bugs.html .
95IEEE/The Open Group 2017 GETS(3P)