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ctype.h |
Header File |
Routines for checking and changing character types
Functions
- _tolower
- Translates uppercase characters to lowercase.
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- _toupper
- Translates uppercase characters to lowercase.
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- isalnum
- Checks whether a character is an alphanumeric.
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- isalpha
- Checks whether a character is a letter.
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- isascii
- Checks whether a character is an ASCII character.
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- iscntrl
- Checks whether a character is a control character.
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- isdigit
- Checks whether a character is a digit.
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- isextalnum
- Checks whether a character is an extended alphanumeric.
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- isextlower
- Checks whether a character is a lowercase, including foreign ones.
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- isextpunct
- Checks whether a character is an extended punctuation character.
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- isextupper
- Checks whether a character is an uppercase, including foreign ones.
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- isfrgn
- Checks whether a character is a foreign letter.
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- isfrgnalnum
- Checks whether a character is a foreign letter which is valid in a variable name.
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- isfrgnlower
- Checks whether a character is a foreign lowercase.
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- isfrgnupper
- Checks whether a character is a foreign uppercase.
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- isgraph
- Checks whether a character is a graph character.
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- isGreek
- Checks whether a character is a Greek letter.
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- islower
- Checks whether a character is a lowercase.
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- isprint
- Checks whether a character is a printing character.
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- ispunct
- Checks whether a character is a punctuation character.
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- isspace
- Checks whether a character is a white space.
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- isupper
- Checks whether a character is an uppercase.
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- isxdigit
- Checks whether a character is a hex digit.
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- toascii
- Translates characters to ASCII format.
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- toextlower
- Translates characters to lowercase, including foreign ones.
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- toextupper
- Translates characters to uppercase, including foreign ones.
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- tolower
- Translates characters to lowercase.
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- toupper
- Translates characters to uppercase.
Note: All of these functions are inline functions which are implemented using GNU C smart macros
(except the simplest ones, which are ordinary macros). Some of them expand to relatively
large code, so if you call any of them more than twice in a program, it will be a good idea
to define an ordinary function which calls this macro. For example, if you want
to call isxdigit more than twice, define the following to save memory:
int _isxdigit(int c)
{
return isxdigit (c);
}
Then call _isxdigit instead.