NAME
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 functions
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.
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)
STANDARDS
These functions, except for digittoint(), isascii(), ishexnumber(), isideogram(), isnumber(), isphonogram(), isrune(), isspecial() and toascii(), conform to ISO/IEC 9899:1990 (“ISO C90”).
HISTORY
The functions isalpha(), isupper(), islower(), isdigit(), isalnum(), isspace(), ispunct(), isprint(), iscntrl(), and isascii() first appeared in Version 7 AT&T UNIX.