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| author | Kaz Kylheku <kaz@kylheku.com> | 2022-04-13 21:16:48 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2022-04-13 21:16:48 -0700 |
| commit | eac4164e94b94e9f5f35e939e181352ddc634446 (patch) | |
| tree | 464ddda43beed9d1dffa387b730a2fb5c133888c | |
| parent | 6e4f7f90eb606c80014c06f19319e190ded43ec8 (diff) | |
| download | cppawk-eac4164e94b94e9f5f35e939e181352ddc634446.tar.gz cppawk-eac4164e94b94e9f5f35e939e181352ddc634446.tar.bz2 cppawk-eac4164e94b94e9f5f35e939e181352ddc634446.zip | |
narg man page: mention narg() returning 1 in BUGS.
| -rw-r--r-- | cppawk-narg.1 | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/cppawk-narg.1 b/cppawk-narg.1 index c0d6c4f..c9f30a0 100644 --- a/cppawk-narg.1 +++ b/cppawk-narg.1 @@ -453,6 +453,24 @@ to produce an identical macro called This then allows for two "recursion" levels, whereby each one uses the macro under a different name. +Both +.B "narg()" +and +.B "narg(x)" +expand to 1. This is a "feature" of the preprocessor: the empty +argument list is indistinguishable from an empty argument, because +preprocessor arguments are not required to be non-empty sequences +of tokens. For instance if +.B mac +is a macro which may be called with two arguments, then +.B "mac(,)" +is a valid call, which passes two empty arguments. Consequently, +if the comma is deleted from the syntax, then there is one empty argument. +The number of arguments is the number of commas plus one. This is why +.B narg +is specified as taking one or more arguments: it is not possible for +any macro to be given fewer arguments than one. + .SH AUTHOR Kaz Kylheku <kaz@kylheku.com> |