error when compiling c++ code with g++

Question

i get error of this type:
"in function ... multiple definition of ..."
"... first defined here"
"warning: size of symbol ... changed from to in "

*the code is compiled with the flags: -ansi -Wall -pedantic-errors -Werror
*STL is used

is there any explanation for that?
thank you in advance

Answer 1

Explanation? The error message you quoted is already an explanation as exhaustive as it can ever get. Something (a variable) is defined more than once in the same scope. The compiler gave you the name of the offending variable. The compiler reported the error at the second definition and supplied an additional message that points out the first definition. That's everything you need to know to find the problem and then some. What more to explain here?