这个Makefile有什么问题

Question

我有以下makefile.如果我这样做make USE_44=1 USE_O=1,我收到以下错误.

makefile:21: *** missing separator,第21行是elif ($(USE_S), 1).

请注意,如果我这样做make USE_44=1,它编译得很好.

有人能告诉我这里的问题是什么,我该如何解决？

USE_44 = 0
USE_IO = 0
USE_O = 0
USE_S = 0
USE_F = 0
USE_I = 0
USE_WL = 0

ifeq ($(USE_44), 0)
    CXX = g++
else
    CXX = g++44
endif

CXXFILES = main.cpp jacobcalc.cpp linkup.cpp slave1.cpp jacobcalc2.cpp slave2.cpp laplacalc.cpp multi.cpp subblock.cpp replication.cpp hash.cpp

CXXFLAGS := -std=c++0x -O3 -o

ifeq ($(USE_O), 1)
    CXXFLAGS += progo -DWITHOUT_LOCKS -DWITHOUT_BARRIERS -DWITHOUT_MPROTECT 
elif ($(USE_S), 1)
    CXXFLAGS += progs -DWITHOUT_LOCKS -DWITHOUT_BARRIERS -DWITHOUT_MPROTECT -DSINGLE
elif ($(USE_F), 1)
    CXXFLAGS += progf -DNEGLECT_DET_LOCKS 
elif ($(USE_I), 1)
    CXXFLAGS += progi -DWITH_INSTR
elif ($(USE_WL), 1)
    CXXFLAGS += progwl -DWITHOUT_LOCKS 
else
    CXXFLAGS += prog
endif

ifeq ($(USE_IO), 1)
    CXXFLAGS += -DWITHOUT_IO
endif

#CFLAGS := $(CFLAGS) -Wall -W -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls -Wdisabled-optimization
#CFLAGS := $(CFLAGS) -Wpadded -Winline -Wpointer-arith -Wsign-compare -Wendif-labels prog
LIBS := -lm -lpthread 

all:
    $(CXX) $(CXXFILES) $(LIBS) $(CXXFLAGS)

clean:
    rm -f prog* *.o

Answer 1

make文档中概述了使用条件的正确方法.

  conditional-directive
  text-if-one-is-true
  else conditional-directive
  text-if-true
  else
  text-if-false
  endif

elif无法识别.如果你改为键入else ifeq(...)它应该都是好的.