https://slackpack.eu/pack.cgi?id=1166
SlackPack: Package details for LibSigC++ 2.2.10 for Intel x86-64
SlackPack: Package details for LibSigC++ 2.2.10 for Intel x86-64
package detailsintel
https://packages.msys2.org/packages/mingw-w64-x86_64-libsigc++
Package: mingw-w64-x86_64-libsigc++ - MSYS2 Packages
packagemingw
https://libsigcplusplus.github.io/libsigcplusplus/reference/html/structsigc_1_1unwrap__reference_3_01std_1_1reference__wrapper_3_01const_01T__type_01_4_01_4.html
libsigc++: sigc::unwrap_reference std::reference_wrapper const T_type Struct Template...
t typeunwrapreferencestd