Below is a little program, made up of two files. It's a reduction of code causing filesystem crashes when compiled with g++ on some, but not all, platforms that gcc supports. It works fine with other compilers. The static version works fine, even with g++, and outputs "all's well that ends well". dll_test stackdumps at the line marked with the comment. Does anyone know what's going on here? Am I supposed to be passing some additional options to g++ when building or using shared libraries? Thanks, --Beman callee.cpp ========== #include <string> void f( std::string & s ) { s = "all's well that ends well"; // dll_test crash! } caller.cpp ========== #include <string> #include <iostream> void f( std::string & s ); int main() { std::string s; f(s); std::cout << s << std::endl; return 0; } Compile and test (cygwin) ========================= g++ -o static_test caller.cpp callee.cpp static_test g++ -c callee.cpp g++ -shared -o callee.dll callee.o g++ -o dll_test caller.cpp -L./ -lcallee dll_test