Question

I have the below Makefile and for some reason it’s dependent on a file, ewapi.c. This file executes some SWIG commands and uses the ewapi.i file. I’ve clear out all the contents of ewapi.c and the Makefile successfully runs. If I remove the ewapi.c file the make file will not complete. The exception stack is below if that helps. Any ideas on how to change the Makefile so its not dependent on ewapi.c?

# BUILD_DIR and DIST_DIR are exported by build.xml
#
CMODE=

SWIG = swig
CC = $(PREFIX)gcc
LD = $(CC) 

OBJ_DIR = $(BUILD_DIR)/obj
AUTOGEN_DIR = $(BUILD_DIR)/auto-generated
PACKAGE_DIR = $(AUTOGEN_DIR)/com/sample/jni

PACKAGE = com.sample.jni

INCLUDES = -I$(JAVA_INCLUDE) \
           -I$(SAMPLE_SDK_DIR)/include \
           -I$(JDK_HOME)/include

LIB_INCLUDES = -L$(SAMPLE_SDK_DIR)/lib

LIBS = /lib/libssl.so.4 \
       /lib/libcrypto.so.4 \
       -lSampleApi \
       -lm

DIRS = $(PACKAGE_DIR) $(DIST_DIR) $(OBJ_DIR) $(AUTOGEN_DIR)

CFLAGS = $(CMODE) -Wall -fpic $(INCLUDES) -O0 -g3
SFLAGS = -java $(INCLUDES) -package $(PACKAGE) -outdir $(PACKAGE_DIR)
LDFLAGS = -shared $(LIB_INCLUDES) $(LIBS)

OBJECTS = $(OBJ_DIR)/ewapi_wrap.o $(OBJ_DIR)/ewapi.o
TARGET = $(DIST_DIR)/libSample.so

all: $(DIRS) $(TARGET)

%_wrap.c: %.i
    $(SWIG) $(SFLAGS) $< 

$(OBJ_DIR)/%.o: %.c
    $(CC) $(CFLAGS) -c $< -o $@

$(TARGET): $(OBJECTS)
    $(LD) $(OBJECTS) $(LDFLAGS) -o $@

$(DIRS):
    mkdir -p $@

clean:
    rm -rf $(TARGET) $(PACKAGE_DIR)/* $(TARGET) $(AUTOGEN_DIR) $(OBJ_DIR)

Exception Stack (when I remove ewapi.c):

[exec] rm ewapi_wrap.c
[exec] make-3.79.1-p7: *** No rule to make target `/test/build/obj/ewapi.o', needed by `/test/dist/libSample.so'.  Stop.

Answer 1

The macros OBJECTS includes $(OBJ_DIR)/ewapi.o; the rule for $(TARGET) says it depends on $(OBJECTS); and the rule for all says it depends on $(TARGET). So, there needs to be a way to create ewapi.o from something – and in the absence of ewapi.c, there is no way to build ewapi.o, hence the complaint you get.

Possible fixes:

• Replace ewapi.c.
• Remove ewapi.o from the macro $(OBJECTS).