https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105741
Bug ID: 105741
Summary: Wrong preprocessor parameter substitution with
##__VA_ARGS__.
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc.gnu.org_bugzilla at jfa dot knudsen.ovh
Target Milestone: ---
This code :
#define CALL2(dummy, p1, ...) "dummy"=dummy, "p1"=p1, "va"=__VA_ARGS__
#define CALL(dummy, ...) CALL2(dummy, ##__VA_ARGS__)
#define CALL_WITHOPT(dummy, ...) CALL2(dummy __VA_OPT__(,) __VA_ARGS__)
#define CALL_ARGS "param1", "param2"
CALL("dum", "param1", "param2");
CALL_WITHOPT("dum", CALL_ARGS);
CALL("dum", CALL_ARGS);
preprocessed gives :
"dummy"="dum", "p1"="param1", "va"="param2";
"dummy"="dum", "p1"="param1", "va"="param2";
"dummy"="dum", "p1"="param1", "param2", "va"=;
We can see that, at the third line, parameter p1 = "param1", "param2" and
__VA_ARGS__ is empty.
It seems that CALL_ARGS expands to "param1", "param2" but is still only one
parameter in the variable list.
Is that the way it is supposed to be ?
Any workaround before it's fixed ?
