extern "C" void cygwin_posix_to_win32_path_list (const char *posix, char *win32);

Given a POSIX path-style string (that is, /foo:/bar), convert to the equivalent Win32 path-style string (that is, d:\;e:\bar). Win32 must point to a sufficiently large buffer.
 

char *_epath;

char *_win32epath;

_epath = _win32epath = getenv (NAME);

/* If we have a POSIX path list, convert to win32 path list */

if (_epath != NULL && *_epath != 0

     && cygwin_posix_path_list_p (_epath))

  {

     _win32epath = (char *) xmalloc

         (cygwin_posix_to_win32_path_list_buf_size (_epath));

     cygwin_posix_to_win32_path_list (_epath, _win32epath);

     }