https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96527
Bug ID: 96527
Summary: __builtin_va_arg_pack_len produces error in documented
sample code
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: bruno at clisp dot org
Target Milestone: ---
Created attachment 49024
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49024&action=edit
Test case
The only documented example of __builtin_va_arg_pack_len, in
https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Constructing-Calls.html ,
produces an error "invalid use of '__builtin_va_arg_pack_len ()'" when actually
used.
Test case foo.c is attached. GCC 5.5.0, 6.5.0, 7.5.0, 8.4.0, 9.3.0, 10.2.0 all
produce an error:
$ gcc -O2 -Wall -S foo.c
foo.c: In function 'myopen':
foo.c:7:7: error: invalid use of '__builtin_va_arg_pack_len ()'
7 | if (__builtin_va_arg_pack_len () > 1)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
