File gtk / gtk.h not found. Even with pkg-config

Question

I create C software using the SDL and GTK + 3 library. My first attempt with GTK + 3 on a specific main.c and its Makefile works fine, but when I try to add my GTK project to another piece of code using my "real "Makefile, even if I added the same flags for GTK +3, I cannot compile and get the gtk/gtk.h file no found error. I visited a lot of threads about this error, but I still can't get this to work.

Here is my old Makefile making it work:

 CC=clang CPPFLAGS= `pkg-config --cflags gtk+-3.0` CFLAGS= -Wall -Wextra -std=c99 -O2 LDFLAGS= LDLIBS= `pkg-config --libs gtk+-3.0` `pkg-config gmodule-2.0 --libs` SRC= main.c OBJ= ${SRC:.c=.o} all: main main: ${OBJ} -lm clean: rm -f *~ *.o main 

And here is the one I use for the project:

 CC=clang CPPFLAGS= `pkg-config --cflags sdl gtk+-3.0` CFLAGS= -Wall -Wextra -Werror -std=c99 -O2 -pedantic LDFLAGS= LDLIBS= `pkg-config --libs sdl` `pkg-config --libs gtk+-3.0` `pkg-config gmodule-2.0 --libs` -lgtk -lgdk -lglib -lX11 -lXext -lSDL -lSDL_image -lm SRCDIR = src OBJDIR = obj BINDIR = bin TARGET = main SOURCES := $(wildcard $(SRCDIR)/*.c) INCLUDES := $(wildcard $(SRCDIR)/*.h) DEPENDS := $(wildcard $(OBJDIR)/*.d) OBJECTS := $(SOURCES:$(SRCDIR)/%.c=$(OBJDIR)/%.o) rm = rm -f all: makedirs $(BINDIR)/$(TARGET) $(BINDIR)/$(TARGET): $(OBJECTS) @$(CC) $(OBJECTS) $(LDLIBS) -o $@ @echo "Linking complete!" $(OBJECTS): $(OBJDIR)/%.o : $(SRCDIR)/%.c @$(CC) $(CFLAGS) -c $< -o $@ @echo "[OK] Compiled "$<"" makedirs: @mkdir -p $(OBJDIR) @mkdir -p $(BINDIR) @echo "[OK] Created directories : $(BINDIR) $(OBJDIR)" [....] etc 

And the error:

 src/main.c:2:14: fatal error: 'gtk/gtk.h' file not found #include <gtk/gtk.h> 

Tanks for attention :)

[EDIT]

 ~ ▶ pkg-config --libs gtk+-3.0 -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 ~ ▶ pkg-config --cflags sdl gtk+-3.0 -D_GNU_SOURCE=1 -D_REENTRANT -pthread -I/usr/include/SDL -I/usr/include/gtk-3.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/at-spi-2.0 -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-linux-gnu/dbus-1.0/include -I/usr/include/gtk-3.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng12 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include 

And the main.c header:

  #include <gtk/gtk.h> #include <stdio.h> #include <stdlib.h> #include "neural.h" 

Answer 1

You just forgot to add CPPFLAGS to the $ (OBJECTS) rule

It should look like this:

 $(OBJECTS): $(OBJDIR)/%.o : 

$(SRCDIR)/% .c@ $(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@

@echo "[OK] Compiled "$<""

Answer 2

As Yu. Verzun said, I forgot to add the CPPFLAGS rule, but not only to OBJECTS:

 $(BINDIR)/$(TARGET): $(OBJECTS) @$(CC) $(OBJECTS) $(LDLIBS) $(CPPFLAGS) -o $@ @echo "Linking complete!" $(OBJECTS): $(OBJDIR)/%.o : $(SRCDIR)/%.c @$(CC) $(CFLAGS) $(CPPFLAGS) -c $< -o $@ @echo "[OK] Compiled "$<"" 

the code here works, notice both of $ (CPPFLAGS). Thank you very much!