Makefile和automake中判断CPU位数

Makefile中:

cpu_bit=$(shell getconf LONG_BIT)
ifeq ($(cpu_bit),64)
    MY_CXXFLAGS=
else
    MY_CXXFLAGS=-march=pentium4
endif
 
x::
        @echo $(cpu_bit)
        @echo $(MY_CXXFLAGS)

 

automake中要稍复杂些:

首先要在configure.ac文件中添加一行:

AM_CONDITIONAL(bit_32,test "x`getconf LONG_BIT`"="x32")

 

然后再在Makefile.am文件中添加:

if bit_32
    MY_CXXFLAGS=-march=pentium4
else
    MY_CXXFLAGS=
endif

 

这样就可以了.