get_field_ea

Get address of the specified field using the type information
     ea         - address of the structure
     field_name - name of the structure field
If the database contains a structure at the specified ea and the
type information is present, this function will return the address of the
structure field.

long get_field_ea(long ea, string field_name);

For example:

  .data:00413060 errtable        dd 1   ; oscode
  .data:00413060                 dd 16h ; errnocode

        msg("address is: %x\n", _errtable.errnocode);

prints 413064. The "_errtable.errnocode" expression is essentially a shortcut for:

get_field_ea(get_name_ea_simple("_errtable"), "errnocode")