创建一个简单的Makefile来构建一个共享库 [英] Creating a simple Makefile to build a shared library

问题描述

我正在尝试创建一个非常基本的手工Makefile，以创建一个共享库来说明这一点.

I am trying to create a very basic hand crafted Makefile to create a shared library to illustrate a point.

这是我到目前为止所拥有的:

This is what I have so far:

SHELL = /bin/sh
CC    = gcc
FLAGS        = -std=gnu99 -Iinclude
CFLAGS       = -fPIC -pedantic -Wall -Wextra -march=native -ggdb3
DEBUGFLAGS   = -O0 -D _DEBUG
RELEASEFLAGS = -O2 -D NDEBUG -combine -fwhole-program

TARGET  = example.so
SOURCES = $(shell echo src/*.c)
HEADERS = $(shell echo include/*.h)
OBJECTS = $(SOURCES:.c=.o)

PREFIX = $(DESTDIR)/usr/local
BINDIR = $(PREFIX)/bin

all: $(TARGET)

$(TARGET): $(OBJECTS)
    $(CC) $(FLAGS) $(CFLAGS) $(DEBUGFLAGS) -o $(TARGET) $(OBJECTS)

当我运行make时，它尝试构建应用程序-ld失败，因为它无法解析main().

When I run make, it attempts to build an application - and ld fails because it can't resolve main().

问题似乎出在CFLAGS上-我指定了-fPIC，但是那不起作用-我在做什么错了?

Problem seems to be with CFLAGS - I have specified -fPIC but that is not working - what am I doing wrong?

我按照建议添加了-shared标志，当我运行make时，出现此错误:

I added the -shared flag as suggested, when I run make, I got this error:

gcc -std=gnu99 -Iinclude -fPIC -shared -pedantic -Wall -Wextra -march=native -ggdb3 -O0 -D _DEBUG -o example.so src/example.o
/usr/bin/ld: src/example.o: relocation R_X86_64_32 against `.rodata' can not be used when making a shared object; recompile with -fPIC
src/example.o: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [example.so] Error 1

似乎建议仅还原为-fPIC.

顺便说一句，我新的CFLAGS设置是:

BTW, my new CFLAGS setting is:

CFLAGS       = -fPIC -shared -pedantic -Wall -Wextra -march=native -ggdb3

我正在Ubuntu 10.0.4上运行gcc v4.4.3.

I am running gcc v4.4.3 on Ubuntu 10.0.4.

推荐答案

解决方案是按如下方式修改XXFLAGS:

The solution was to modify the XXFLAGS as follows:

FLAGS        = # -std=gnu99 -Iinclude
CFLAGS       = -fPIC -g #-pedantic -Wall -Wextra -ggdb3
LDFLAGS      = -shared

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