iswhite
#define iswhite(ch) (ch == ' ' || ch == '\t')
#define iswhite(arg) (_wht[arg]) /* T if char is white */
iswhite(int c)
#define iswhite(ch) ((ch) == ' ' || (ch) == '\t')
#define iswhite(ch) ((ch) == ' ' || (ch) == '\t')
#define iswhite(c) ((c) == ' ' || (c) == '\t' || (c) == '\n' || (c) == '\f')
#define iswhite(x) testbits((x)->gch.marked, WHITEBITS)
#define iswhite(ch) ((ch) == ' ' || (ch) == '\t')