c++ - Undefined reference to function when linking -

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trying make c++ program splitting line , creating 2 std::vector save elements said line. function call:

void readconf(const char *name, std::vector<t_objectlibrary> libs, std::vector<iobject *> &objs, std::vector<iobject *> &timer) 

i placed in inside config.hpp has it's prototype :

void readconf(const char *name, std::vector<t_objectlibrary> libs,std::vector<iobject *> &objs, std::vector<iobject *> timer); 

and in main call :

int main(int ac, char **av) {   std::vector<iobject *>        objs;   std::vector<iobject *>        timer;   std::vector<t_objectlibrary>  libs;   libs = lib_read("./src/objectlibrary");   readconf("config.txt", libs, objs, timer);  ... } 

yet error message when compile makefile. fine until last message of compilation says :

here makefile use (asked in comments) :

11 │ src     =       src/getvalue.cpp \ 12 │                 src/iobject.cpp \ 13 │                 src/attributes.cpp \ 14 │                 src/dynamic_lib.cpp \ 15 │                 src/config.cpp \ 16 │                 src/color.cpp \ 17 │                 src/main.cpp 18 │  19 │ obj     =       $(src:.cpp=.o) 20 │  21 │ name    =       conf 22 │  23 │ cxx     =       g++ -std=c++11 -wall -wextra -lsfml-graphics -lsfml-window -lsfml-system -fpic 24 │  25 │ rm      =       rm -f 26 │  27 │ all:    $(name) $(obj) 28 │  29 │ $(name):        $(obj) 30 │                 $(cxx) $(obj) -o $(name) -ldl 31 │  32 │ clean: 33 │                 $(rm) $(obj) 34 │  35 │ fclean: clean 36 │                 $(rm) $(name) 37 │  38 │ re:     fclean 39 │  40 │ .phony: clean fclean re 

the function signature in hpp doesn't match in declaration.