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| -rw-r--r-- | cppawk.1 | 22 |
1 files changed, 22 insertions, 0 deletions
@@ -303,6 +303,28 @@ and .B --prepro command line options. +The C preprocessor doesn't permit macro recursion, which introduces +limitations to the ability to compose invocations of +.B cppawk +macros, thus curtailing their power. +If in the expansion of +some macro +.B M +a call of macro +.B M +appears, that call is not expanded. This is relied upon by C programs which +use macros to inline same-named functions, for instance, if it were +acceptable for the argument of +.B strlen +to be evaluated twice, then this macro version would be permissible: +.ft B + #define strlen(x) (*(x) == 0 ? 0 : strlen(x)) +.ft R +Here, the +.B strlen +call in the macro expansion is relied upon not to be expanded as a macro, +in which case runaway expansion would occur. + .SH AUTHOR Kaz Kylheku <kaz@kylheku.com> |