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.
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13 gets — get a string from a stdin stream
14
16 #include <stdio.h>
17 char *gets(char *s);
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21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
24 defers to the ISO C standard.
25 The gets() function shall read bytes from the standard input stream,
27 stdin, into the array pointed to by s, until a <newline> is read or an
28 end-of-file condition is encountered. Any <newline> shall be discarded
29 and a null byte shall be placed immediately after the last byte read
30 into the array.
31 The gets() function may mark the last data access timestamp of the file
33 associated with stream for update. The last data access timestamp shall
34 be marked for update by the first successful execution of fgetc(),
35 fgets(), fread(), fscanf(), getc(), getchar(), getdelim(), getline(),
36 gets(), or scanf() using stream that returns data not supplied by a
37 prior call to ungetc().
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40 Upon successful completion, gets() shall return s. If the end-of-file
41 indicator for the stream is set, or if the stream is at end-of-file,
42 the end-of-file indicator for the stream shall be set and gets() shall
43 return a null pointer. If a read error occurs, the error indicator for
44 the stream shall be set, gets() shall return a null pointer, and set
45 errno to indicate the error.
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48 Refer to fgetc().
49 The following sections are informative.
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53 None.
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56 Reading a line that overflows the array pointed to by s results in
57 undefined behavior. The use of fgets() is recommended.
58 Since the user cannot specify the length of the buffer passed to
60 gets(), use of this function is discouraged. The length of the string
61 read is unlimited. It is possible to overflow this buffer in such a way
62 as to cause applications to fail, or possible system security viola‐
63 tions.
64 Applications should use the fgets() function instead of the obsolescent
66 gets() function.
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69 The standard developers decided to mark the gets() function as obsoles‐
70 cent even though it is in the ISO C standard due to the possibility of
71 buffer overflow.
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74 The gets() function may be removed in a future version.
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77 Section 2.5, Standard I/O Streams, feof(), ferror(), fgets()
78 The Base Definitions volume of POSIX.1‐2008, <stdio.h>
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82 Portions of this text are reprinted and reproduced in electronic form
83 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
84 -- Portable Operating System Interface (POSIX), The Open Group Base
85 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
86 cal and Electronics Engineers, Inc and The Open Group. (This is
87 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
88 event of any discrepancy between this version and the original IEEE and
89 The Open Group Standard, the original IEEE and The Open Group Standard
90 is the referee document. The original Standard can be obtained online
91 at http://www.unix.org/online.html .
92 Any typographical or formatting errors that appear in this page are
94 most likely to have been introduced during the conversion of the source
95 files to man page format. To report such errors, see https://www.ker‐
96 nel.org/doc/man-pages/reporting_bugs.html .
97IEEE/The Open Group 2013 GETS(3P)