boost::ut::detail::cfg::{largc,largv} are initialized with garbage on alpine linux.

[tomboehmer]

Expected Behavior

__attribute__((constructor(101))) inline void cmd_line_args should initialize the largc and largv from actual argc and argv.

Actual Behavior

• largc gets set to a different, seemingly random, integer in each run
• use of largv leads to a segfault in boost::ut::detail::cfg::parse when assigning to executable_name
• happens for both clang and gcc
• If I remove the cmd_line_args function then largc and largv retain their default values of zero: so at least the function gets called
• i assume this is a musl problem since it works fine on debian with glibc

Steps to Reproduce the Problem

1. Run on alpine linux: podman run --rm -it alpine:3.20 ash
2. apk add g++
3. g++ -o main.out -D BOOST_UT_DISABLE_MODULE=1 -std=c++20 ut_test.cpp

// ut_test.cpp

#include "ut.hpp"                                                                                        
                                                                                                         
int main() {                                                                                             
    std::cerr << "cfg::largc: " << boost::ut::detail::cfg::largc << '\n';                                
    std::cerr << "cfg::largv: " << boost::ut::detail::cfg::largv << '\n';                                
    return 0;                                                                                            
}

Specifications

• Version: latest git commit from master: aefa901
• Platform: Alpine Linux 3.20