1ISDIGIT(P)                 POSIX Programmer's Manual                ISDIGIT(P)
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NAME

6       isdigit - test for a decimal digit
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SYNOPSIS

9       #include <ctype.h>
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11       int isdigit(int c);
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DESCRIPTION

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.
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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.
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RETURN VALUE

25       The isdigit() function shall return non-zero if c is a  decimal  digit;
26       otherwise, it shall return 0.
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ERRORS

29       No errors are defined.
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31       The following sections are informative.
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EXAMPLES

34       None.
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APPLICATION USAGE

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.
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RATIONALE

42       None.
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FUTURE DIRECTIONS

45       None.
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SEE ALSO

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>
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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 .
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65IEEE/The Open Group                  2003                           ISDIGIT(P)
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