Makefile macro definition, makefile macro

Source: Internet
Author: User

Makefile macro definition, makefile macro
Cause: when I read the linux0.11 code, I found that the macro RAMDISK is defined in makefile. I have never touched on this kind of usage before.


Objective: To use the macro defined in Makefile in the C language code.


Makefile content:


CC = gcc


RAMDISK =-DRAMDISK = 512


All:
$ (CC) $ (RAMDISK) hello. c
Clean:
Rm-f a. out
-------------------------------------------------------------------
Hell. c


# Include <stdio. h>


Int main (void)
{
# Ifdef RAMDISK

Printf ("RAMDISK = % d \ n", RAMDISK );

# Else
Printf ("no ramdisk \ n ");
# Endif
Return 0;

}


In summary, it is to add parameters to gcc.

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