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ctype(3) [osx man page]

CTYPE(3)						   BSD Library Functions Manual 						  CTYPE(3)

digittoint, isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, ishexnumber, isideogram, islower, isnumber, isphonogram, isprint, ispunct, isrune, isspace, isspecial, isupper, isxdigit, toascii, tolower, toupper -- character classification macros LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <ctype.h> int digittoint(int c); int isalnum(int c); int isalpha(int c); int isascii(int c); int iscntrl(int c); int isdigit(int c); int isgraph(int c); int ishexnumber(int c); int isideogram(int c); int islower(int c); int isnumber(int c); int isphonogram(int c); int isspecial(int c); int isprint(int c); int ispunct(int c); int isrune(int c); int isspace(int c); int isupper(int c); int isxdigit(int c); int toascii(int c); int tolower(int c); int toupper(int c); DESCRIPTION
The above functions perform character tests and conversions on the integer c. They are available as macros, defined in the include file <ctype.h>, or as true functions in the C library. See the specific manual pages for more information. Extended locale versions of these functions are documented in ctype_l(3). See xlocale(3) for more information. SEE ALSO
digittoint(3), isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), isideogram(3), islower(3), isphonogram(3), isprint(3), ispunct(3), isrune(3), isspace(3), isspecial(3), isupper(3), isxdigit(3), toascii(3), tolower(3), toupper(3), wctype(3), ascii(7), ctype_l(3) STANDARDS
These functions, except for digittoint(), isascii(), ishexnumber(), isideogram(), isnumber(), isphonogram(), isrune(), isspecial() and toascii(), conform to ISO/IEC 9899:1990 (``ISO C90''). BSD
March 30, 2004 BSD

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CTYPE(3)						   BSD Library Functions Manual 						  CTYPE(3)

isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isblank, toupper, tolower, -- character classification and mapping functions LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <ctype.h> isalpha(int c); isupper(int c); islower(int c); isdigit(int c); isxdigit(int c); isalnum(int c); isspace(int c); ispunct(int c); isprint(int c); isgraph(int c); iscntrl(int c); isblank(int c); toupper(int c); tolower(int c); DESCRIPTION
The above functions perform character tests and conversions on the integer c. See the specific manual pages for information about the test or conversion performed by each function. EXAMPLES
To print an upper-case version of a string to stdout, the following code can be used: const char *s = "xyz"; while (*s != '') { putchar(toupper((int)(unsigned char)*s)); s++; } SEE ALSO
isalnum(3), isalpha(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), tolower(3), toupper(3), ascii(7) STANDARDS
These functions, with the exception of isblank(), conform to ANSI X3.159-1989 (``ANSI C89''). All described functions, including isblank(), also conform to IEEE Std 1003.1-2001 (``POSIX.1''). CAVEATS
The first argument of these functions is of type int, but only a very restricted subset of values are actually valid. The argument must either be the value of the macro EOF (which has a negative value), or must be a non-negative value within the range representable as unsigned char. Passing invalid values leads to undefined behavior. Values of type int that were returned by getc(3), fgetc(3), and similar functions or macros are already in the correct range, and may be safely passed to these ctype functions without any casts. Values of type char or signed char must first be cast to unsigned char, to ensure that the values are within the correct range. The result should then be cast to int to avoid warnings from some compilers. Casting a negative-valued char or signed char directly to int will produce a negative-valued int, which will be outside the range of allowed values (unless it happens to be equal to EOF, but even that would not give the desired result). BSD
May 6, 2010 BSD
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