'"SDL.h" no such file or directory found' when compiling

Most times SDL is in /usr/include/SDL. If so then your #include <SDL.h> directive is wrong, it should be #include <SDL/SDL.h>.

An alternative for that is adding the /usr/include/SDL directory to your include directories. To do that you should add -I/usr/include/SDL to the compiler flags...

If you are using an IDE this should be quite easy too...

If the header file is /usr/include/sdl/SDL.h and your code has:

#include "SDL.h"

You need to either fix your code:

#include "sdl/SDL.h"

Or tell the preprocessor where to find include files:

CFLAGS = ... -I/usr/include/sdl ...

header file lives at

/usr/include/SDL/SDL.h

       __OR__

/usr/include/SDL2/SDL.h  #  for SDL2

in your c++ code pull in this header using

#include <SDL.h>

       __OR__

#include <SDL2/SDL.h>    // for SDL2

you have the correct usage of

sdl-config --cflags --libs

       __OR__

sdl2-config --cflags --libs   #  sdl2

which will give you

-I/usr/include/SDL -D_GNU_SOURCE=1 -D_REENTRANT
-L/usr/lib/x86_64-linux-gnu -lSDL

       __OR__

-I/usr/include/SDL2 -D_REENTRANT
-lSDL2

at times you may also see this usage which works for a standard install

pkg-config --cflags --libs sdl

       __OR__

pkg-config --cflags --libs sdl2   #  sdl2

which supplies you with

-D_GNU_SOURCE=1 -D_REENTRANT -I/usr/include/SDL -lSDL

       __OR__

-D_REENTRANT -I/usr/include/SDL2 -lSDL2   #  SDL2

For Simple Direct Media Layer 2 (SDL2), after installing it on Ubuntu 16.04 via:

sudo apt-get install libsdl2-dev

I used the header:

#include <SDL2/SDL.h>  

and the compiler linker command:

-lSDL2main -lSDL2 

Additionally, you may also want to install:

apt-get install libsdl2-image-dev  
apt-get install libsdl2-mixer-dev  
apt-get install libsdl2-ttf-dev  

With these headers:

#include <SDL2/SDL_image.h>
#include <SDL2/SDL_ttf.h>
#include <SDL2/SDL_mixer.h>  

and the compiler linker commands:

-lSDL2_image 
-lSDL2_ttf 
-lSDL2_mixer