https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110854
Bug ID: 110854
Summary: constructor of std::counting_semaphore is not
constexpr
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: cooky.ykooc922 at gmail dot com
Target Milestone: ---
from [thread.sema#lib:counting_semaphore,constructor]:
constexpr explicit counting_semaphore(ptrdiff_t desired);
but this snippet of code won't compile for gcc >= 11.1 with -std=c++20
=========================================
#include <semaphore>
constinit std::binary_semaphore sem {0};
int main() {}
=========================================
with the following error:
<source>:3:33: error: 'constinit' variable 'sem' does not have a constant
initializer
3 | constinit std::binary_semaphore sem {0};
| ^~~
<source>:3:39: error: call to non-'constexpr' function
'std::counting_semaphore<__least_max_value>::counting_semaphore(std::ptrdiff_t)
[with long int __least_max_value = 1; std::ptrdiff_t = long int]'
3 | constinit std::binary_semaphore sem {0};
| ^
In file included from <source>:1:
/opt/compiler-explorer/gcc-trunk-20230730/include/c++/14.0.0/semaphore:55:16:
note:
'std::counting_semaphore<__least_max_value>::counting_semaphore(std::ptrdiff_t)
[with long int __least_max_value = 1; std::ptrdiff_t = long int]' declared here
55 | explicit counting_semaphore(ptrdiff_t __desired) noexcept
| ^~~~~~~~~~~~~~~~~~
Compiler returned: 1
