A token is the basic lexical unit of the language.
All source input must be formed into valid tokens
by translation phase seven.
Preprocessing tokens (pp-tokens) are a superset of regular tokens.
Preprocessing tokens allow the source file to contain
non-token character sequences that constitute valid preprocessing tokens
There are four categories of preprocessing tokens:
Header filenames, meant to be taken as a single token.
All other single characters that are not otherwise (regular) tokens.
See the example in
Identifiers, numeric constants, character constants, string literals,
operators, and punctuators.
A preprocessing number is made up of a digit,
optionally preceded by a period, and may be
followed by letters, underscores, digits, periods,
and any one of: e+ e- E+ E-.
Preprocessing numbers include
all valid number tokens, plus some
that are not valid number tokens.
For example, in the macro definition:
#define R 2e ## 3
the preprocessing number 2e is not a valid number.
However, the preprocessing operator ##
will ``paste'' it together with the preprocessing number 3
when R is replaced,
resulting in the preprocessing number 2e3,
which is a valid number.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003