Section 2: Compiler
97
TI
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89 / TI
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92 Plus Sierra C Assembler Reference Manual
Not for Distribution
Beta Version February 2, 2001
2.16.3.2. The # Operator (stringizing)
If a parameter in the replacement list is immediately preceded by the ' # '
preprocessing operator, the ' # ' operator and the parameter are both replaced by
a string literal that contains the spelling of the corresponding argument. The
argument (not expanded) is placed within a pair of double quotes with any
whitespace before and/or after the argument removed. Other than the removal of
leading and trailing whitespace, the exact spelling of the argument is retained in
the string.
2.16.3.3. The ## Operator (concatenation)
If a parameter in the replacement list is immediately preceded or followed by the
' ## ' preprocessing operator, the parameter is replaced by the macro-expanded
corresponding argument. For both object-like and function-like macro
invocations, each instance of the ' ## ' preprocessing operator in the replacement
list (not brought in by an argument) is deleted and the preceding and following
preprocessing tokens are concatenated before the list is reexamined for macro
names to be replaced. The token created by concatenation is then available for
further macro replacement as is any other token in the replacement list.
2.16.3.4. Rescanning and Further Replacement
After all parameters in the replacement list have been substituted as described
above, the resulting tokens are rescanned for more macro names to replace. If
the name of the macro being replaced is encountered during this scan of the
replacement list, it is not replaced. Further, if any nested replacements encounter
the name of the nested macro being replaced, it is not replaced. These
nonreplaced macro names are not available for further replacement even if they
are examined again in a context where they would otherwise be replaced.
Finally, if the fully expanded preprocessor token sequence resembles a
preprocessing directive, it is not recognized as such.
2.16.4. Macro Redefinition
An identifier currently defined as an object-like macro may be redefined by
another
#define
directive provided that the second definition is also an object-like
macro definition and the two replacement lists are identical. An identifier currently
defined as a function-like macro may be redefined provided that the second
definition is also a function-like macro definition and both the number of
parameters and the replacement lists are identical.
Two replacement lists are considered identical if and only if the two lists have
identical spelling and whitespace separation. If it is necessary to redefine a
macro and the second definition has a different replacement list, a
#undef
directive must appear before the redefinition.
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