Missing symbols of C++26 contracts in libstdc++exp on Windows

[pointertobios-bmt]

• Version: Relese 2.8.0
• OS: Windows 10

Compile with -fcontracts -lstdc++exp.
Link error:

[build] \w64devkit\bin/ld.exe: .cpp.obj: in function __tu_has_violation': [build].cpp:26:(.text+0x384): undefined reference to handle_contract_violation(std::contracts::contract_violation const&)'
[build] \w64devkit\bin/ld.exe:.cpp.obj: in function __tu_has_violation_exception': [build] .cpp:26:(.text+0x3ed): undefined reference to handle_contract_violation(std::contracts::contract_violation const&)'

[Peter0x44]

Can you provide the source code?

[pointertobios-bmt]

Just try contract_assert(1+1==2)

[Peter0x44]

note the contract_assert has to be in a function

I can reproduce this (and it works with gcc 16 on Linux). I will take a look tomorrow.

[pointertobios-bmt]

oh i'm using this on Windows
I tried it on linux too, it works

[Peter0x44]

Yeah, I was just making sure it isn't something broken also upstream on a more favored/tested platform.

[ssbssa]

See gcc bug 124263.

[skeeto]

Thanks, for the report @pointertobios-bmt and @ssbssa for that informative upstream report. c55e415 adds a temporary patch to work around it until it's fixed upstream. Does that work for you? You can grab the CI build when it's done if you can't build yourself.

[pointertobios-bmt]

Ok got it

[pointertobios-bmt]

thanks

[Peter0x44]

I have other patches to binutils that might fix this weak symbol issue. I submitted them upstream but would be good to test if they help this issue too.