c++ - Why can I not include this file correctly using a makefile? -

my directory structure looks this:

root   |____sg   |     |   |     |____makefile   |     |____simple_client_main.cpp   |   |___eee         |___my_utils.h 

sg base of operations building "simple_client", , i'm running make here. in simple_client_main.cpp have following #includes:

#include <iostream> #include <string>  #include "my_utils.h" 

so need makefile know my_utils.h is. in mind, want add root/eee directory include directory. (from am, ../eee.)

following advice suggested here, makefile looks this:

dir1 = ../eee  cxxflags = $(flag)  objs = simple_client_main.o srcs = simple_client_main.cpp  all: simple_client  simple_client: $(objs)         g++ -o simple_client -i$(dir1) $(objs) -lz  # [...]  depend:         makedepend -- $(cflags) -- $(srcs) 

but doesn't work:

simple_client_main.cpp:6:25: fatal error: my_utils.h: no such file or directory  compilation terminated. 

note if manually set #include directive in cpp follows:

#include "../eee/my_utils.h" 

...everything works expected.

what doing wrong here?

you need add -i$(dir1) either cflags or cxxflags (or perhaps both), when object file compiled, option present in compiler command line.

you want make execute similar to:

g++ -c -i../eee simple_client_main.cpp 

it should if add -i../eee $(cxxflags) or $(cflags). need know rules used make program you're using — can vary.

when linking object files, late -i option of relevance (but should still include $(cflags) or $(cxxflags) in linker command line other options, notably -g, of relevance when linking when compiling object code).

here simple modifications outline makefile shown in question.

dir1     = ../eee iflags   = -i$(dir1) cxxflags = $(flag) $(iflags) cflags   = $(iflags) ldflags  = ldlibs   = -lz cxx      = g++  objs = simple_client_main.o srcs = simple_client_main.cpp  all: simple_client  simple_client: $(objs)         $(cxx) -o $@ $(cxxflags) $(objs) $(ldflags) $(ldlibs) 

a makefile stands modest chance of working correctly. not clear might put in flag macro, i've left it. (i use uflags , uxxflags 'user-defined c (or c++) flags'; can set on command line , never set makefile , included in cflags or cxxflags — may after similar.)

note how linking line macros. normal , desirable; macros can changed when running make without editing makefile, constant text cannot changed without editing makefile. -c , -o options c , c++ compilers should ever appear plain text.

if there still problems, @ built-in rule compiling c++ source code object file, , tweak definitions accordingly. (you can use make -p print rules — may need find out going on, hope not sake because tend complex. using make -f /dev/null -p shows built-in rules only; can useful, too.)

note make depend rule may need surgery. uses $(cflags). if $(cxxflags) contains options needed makedepend command, may need instead, or well. if have c++ source, need $(cxxflags) macro in command line.