TMS34010 C Compiler - Al Kossow's Bitsavers

#define/#undef
Define/Undefine Constant Directives
Syntax
Description
#define name[(arg, ... ,arg)] token-string
#undef name
The preprocessor supports two directives for defining and undefining constants:
• The #define directive assigns a string to a constant. Subsequent
occurrences of name are replaced by token-string. The name can be
immediately followed by an argument list; the arguments are separated
by commas, and the list is enclosed in parentheses. Each occurrence
of an argument is replaced by the corresponding set of
tokens from the comma-separated string.
When a macro with arguments is expanded, the arguments are placed
into the expanded token-string unchanged. After the entire tokenstring
is expanded, the preprocessor scans again for names to expand
at the beginning of the newly created token-string, which allows for
nested macros.
Note that there is no space between name and the open parenthesis
at the beginning of the argument list. A trailing semicolon is not required;
if used, it is treated as part of the token-string.
• The #undef directive undefines the constant name; that is, it causes
the preprocessor to forget the definition of name.
Example
The following example defines the constant f:
#define f(a,b,c) 3*a+b-c
The following line of code uses the definition of f:
f(27,begin,minus)
This line is expanded to:
3*27+begin-minus
To undefine f, enter:
#undef
f
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