https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68665
--- Comment #2 from Robert Shuler <mc1soft at yahoo dot com> --- Results of that suggestion: $ gcc -lcygquadmath -o test128a test128a.c /usr/lib/gcc/i686-pc-cygwin/4.9.3/../../../../i686-pc-cygwin/bin/ld: cannot find -lcygquadmath collect2: error: ld returned 1 exit status Is that the correct way to enter it? I have dll's containing the required functions, two different ones, and several copies of each. I tried variations on your suggestion using the names of these dlls with the same result, though I did not specify a path. The path indicated in the error message does not seem to match anything in my installation. I am attaching a search listing on everything with "quad" in the name. By the way, during installation I selected everything related to "quad."