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@(#)ctype.3 6.5 (Berkeley) 4/19/91
.Dd January 18, 2007 .Dt CTYPE 3 .Os .Sh NAME .Nm isalpha , .Nm isupper , .Nm islower , .Nm isdigit , .Nm isxdigit , .Nm isalnum , .Nm isspace , .Nm ispunct , .Nm isprint , .Nm isgraph , .Nm iscntrl , .Nm isblank , .Nm toupper , .Nm tolower , .Nd character classification and mapping functions .Sh LIBRARY .Lb libc .Sh SYNOPSIS n ctype.h .Fa int c
.Fn isalpha c .Fn isupper c .Fn islower c .Fn isdigit c .Fn isxdigit c .Fn isalnum c .Fn isspace c .Fn ispunct c .Fn isprint c .Fn isgraph c .Fn iscntrl c .Fn isblank c .Fn toupper c .Fn tolower c .Sh DESCRIPTION The above functions perform character tests and conversions on the integer .Ar c .
p See the specific manual pages for more information. .Sh EXAMPLES To print an upper-case version of a string on stdout, use the following code: d -literal const char *s = ...; while (*s != '\\0') { putchar(toupper((unsigned char)*s)); s++; } .Ed .Sh SEE ALSO .Xr isalnum 3 , .Xr isalpha 3 , .Xr isblank 3 , .Xr iscntrl 3 , .Xr isdigit 3 , .Xr isgraph 3 , .Xr islower 3 , .Xr isprint 3 , .Xr ispunct 3 , .Xr isspace 3 , .Xr isupper 3 , .Xr isxdigit 3 , .Xr tolower 3 , .Xr toupper 3 , .Xr ascii 7 .Sh STANDARDS These functions, with the exception of .Fn isblank , conform to .St -ansiC . .Sh CAVEATS The first parameter of these functions is of type int, but only a very restricted subset is actually valid as an argument. The argument must either be the value of the macro .Dv EOF or representable as an unsigned char. Otherwise the behavior is undefined. When testing an expression having the type .Tn plain char , the argument should be cast to an unsigned char.