42 lines
1.4 KiB
Groff
42 lines
1.4 KiB
Groff
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NAME
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isalpha, isupper, islower, isdigit, isxdigit, isalnum,
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isspace, ispunct, isprint, isgraph, iscntrl, isascii -
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classify characters
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SYNTAX
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#include <ctype.h>
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int isalpha (c)
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int c;
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. . .
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DESCRIPTION
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These macros classify character-coded integer values by
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table lookup. Each is a predicate returning nonzero for
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true, zero for false. Isascii is defined on all integer
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values; the rest are defined only where isascii is true and
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on the single non-ASCII value EOF [-1 - see stdio(3S)].
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isalpha c is a letter.
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isupper c is an upper-case letter.
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islower c is a lower-case letter.
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isdigit c is a digit [0-9].
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isxdigit c is a hexadecimal digit [0-9], [A-F] or [a-
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f].
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isalnum c is an alphanumeric (letter or digit).
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isspace c is a space, tab, carriage return, new-line,
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vertical tab, or form-feed.
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ispunct c is a punctuation character (neither control
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nor alphanumeric).
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isprint c is a printing character, code 040 (space)
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through 0176 (tilde).
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isgraph c is a printing character, like isprint
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except false for space.
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iscntrl c is a delete character (0177) or an ordinary
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control character (less than 040).
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isascii c is an ASCII character, code less than 0200.
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DIAGNOSTICS
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If the argument to any of these macros is not in the domain
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of the function, the result is undefined.
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SEE ALSO
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stdio(3S), ascii(5).
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