ctype.h

Macros

_C                X
_L                X
_N                X
_P                X
_S                X
_U                X
_X                X
isalnum           X
isalpha           X
isascii           X
iscntrl           X
isdigit           X
islower           X
isprint           X
ispunct           X
isspace           X
isupper           X
isxdigit          X
toascii           X
tolower           X
tonum             X
toupper           X

   1: /*
   2:  * Macros for determining character type.
   3:  *
   4:  * The table chrtype (in char.c) classifies each character
   5:  *  in one of the categories defined below.
   6:  */
   7: 
   8: #define _U  01      /* upper case */
   9: #define _L  02      /* lower case */
  10: #define _N  04      /* digit */
  11: #define _S  010     /* space */
  12: #define _P  020     /* punctuation */
  13: #define _C  040     /* control */
  14: #define _X  0100        /* hex digit (a-f) */
  15: 
  16: extern  char    ctype[];
  17: 
  18: #define isalpha(c)  (ctype[(c)&0377]&(_U|_L))
  19: #define isupper(c)  (ctype[(c)&0377]&_U)
  20: #define islower(c)  (ctype[(c)&0377]&_L)
  21: #define isdigit(c)  (ctype[(c)&0377]&_N)
  22: #define isxdigit(c) (ctype[(c)&0377]&(_N|_X))
  23: #define isspace(c)  (ctype[(c)&0377]&_S)
  24: #define ispunct(c)  (ctype[(c)&0377]&_P)
  25: #define isalnum(c)  (ctype[(c)&0377]&(_U|_L|_N))
  26: #define isprint(c)  (ctype[(c)&0377]&(_P|_U|_L|_N))
  27: #define iscntrl(c)  (ctype[(c)&0377]&_C)
  28: #define isascii(c)  ((unsigned)(c)<=0177)
  29: #define toupper(c)  (((c)&0377)-'a'+'A')
  30: #define tolower(c)  (((c)&0377)-'A'+'a')
  31: #define toascii(c)  (((c)&0177)
  32: #define tonum(c)    (isdigit(c)?(c)-'0':10+(((c)|(040))-'a'))