1ISDIGIT(P) POSIX Programmer's Manual ISDIGIT(P)
2
3
4
6 isdigit - test for a decimal digit
7
9 #include <ctype.h>
10
11 int isdigit(int c);
12
13
15 The isdigit() function shall test whether c is a character of class
16 digit in the program's current locale; see the Base Definitions volume
17 of IEEE Std 1003.1-2001, Chapter 7, Locale.
18
19 The c argument is an int, the value of which the application shall
20 ensure is a character representable as an unsigned char or equal to the
21 value of the macro EOF. If the argument has any other value, the behav‐
22 ior is undefined.
23
25 The isdigit() function shall return non-zero if c is a decimal digit;
26 otherwise, it shall return 0.
27
29 No errors are defined.
30
31 The following sections are informative.
32
34 None.
35
37 To ensure applications portability, especially across natural lan‐
38 guages, only this function and those listed in the SEE ALSO section
39 should be used for character classification.
40
42 None.
43
45 None.
46
48 isalnum() , isalpha() , iscntrl() , isgraph() , islower() , isprint() ,
49 ispunct() , isspace() , isupper() , isxdigit() , the Base Definitions
50 volume of IEEE Std 1003.1-2001, Chapter 7, Locale, <ctype.h>
51
53 Portions of this text are reprinted and reproduced in electronic form
54 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
55 -- Portable Operating System Interface (POSIX), The Open Group Base
56 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
57 Electrical and Electronics Engineers, Inc and The Open Group. In the
58 event of any discrepancy between this version and the original IEEE and
59 The Open Group Standard, the original IEEE and The Open Group Standard
60 is the referee document. The original Standard can be obtained online
61 at http://www.opengroup.org/unix/online.html .
62
63
64
65IEEE/The Open Group 2003 ISDIGIT(P)