Question

I’m using VS 2008 and compile my application with Multi-threaded Debug (/MTd).
At link time I receive the following error:

error LNK2001: unresolved external symbol __environ

Where the symbol is defined?

Thanks
Dima

Answer 1

When you are using /Md (or variants), the symbols _environ and _wenviron are replaced by function calls. You need to track down the code that uses these (obsolete and deprecated) symbols, and make them use the proper function names. I found lots of people with the same problem as you in google also.

I found some more detail here:

Polling _environ in a Unicode context
is meaningless when /MD or /MDd
linkage is used. For the CRT DLL, the
type (wide or multibyte) of the
program is unknown. Only the multibyte
type is created because that is the
most likely scenario.

If you change the use of the symbol _environ to the wide character version _wenviron, your original code will probably work.