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For example, an array of 256 eight-bit integers, arranged as bitfields, is created, where each bit corresponds to a particular property of the character, e.g., isdigit, isalpha. If the lowest-order bit of the integers corresponds to the isdigit property, the code could be written as
294:. These functions are used to test characters for membership in a particular class of characters, such as alphabetic characters, control characters, etc. Both single-byte, and wide characters are supported.
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Unlike the above example, the character classification routines are not written as comparison tests. In most C libraries, they are written as static table lookups instead of macros or functions.
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This can cause problems if when the macro expands, the expression substituted for
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The classification is evaluated according to the effective locale.
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117:Learn how and when to remove this message
542:checks whether the operand is lowercase
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403:#define isdigit(x) (TABLE & 1)
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178:Localization
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107:October 2011
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44:verification
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1305:Objective-C
1086:Windows CRT
428:side effect
374:'z'
356:'a'
344:'Z'
326:'A'
163:Mathematics
1281:Descendant
1153:Norcroft C
979:Data types
928:Embedded C
827:References
482:character
477:character
365:&&
335:&&
148:Data types
77:newspapers
1283:languages
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1057:libhybris
959:Operators
949:Functions
819:towctrans
779:towctrans
594:iswxdigit
466:in C++).
173:Date/time
1378:Category
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460:wctype.h
290:for the
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216:assert.h
1224:Eclipse
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742:toupper
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568:isdigit
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530:islower
511:isalpha
492:isalnum
464:cwctype
452:ctype.h
440:isdigit
384:ctype.h
298:History
225:errno.h
193:Signals
158:Strings
91:scholar
18:Ctype.h
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1101:uClibc
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316:true
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