Makefile修改以支持c++11。

I am able to compile a single file using gcc with -std=c++0x option. But I can't do this through makefile. Here are the set of flags in my makefile (which after make complains about c++11 keywords):

我可以使用gcc和-std=c++0x选项编译一个文件。但是我不能通过makefile来实现。这里是我的makefile中的一组标志(在对c++11关键字进行了抱怨之后):

MACHINE = $(shell echo `uname -s`-`uname -m` | sed "s/ //g")
CCC     = CC
CCC     = g++
CFLAGS  = -O3
CFLAGS  = -std=c++0x
CFLAGS  = -pg -D_DEBUG -g -c -Wall
LFLAGS  = -O
LFLAGS  = -pg -g

What am I missing?

我缺少什么?

Edit: I changed it to the following, but I still get compile errors, which I don't get with command line gcc invocation.

编辑:我将其更改为以下内容，但仍然会出现编译错误，我无法使用命令行gcc调用。

CXXFLAGS=-O3 -std=c++0x -pg -D_DEBUG -g -c -Wall

3 个解决方案

#1

This way your makefile will use all of your CFLAGS:

这样，makefile将使用所有的CFLAGS:

CFLAGS=-O3 -std=c++0x -pg -D_DEBUG -g -c -Wall

You're overriding them with each "CFLAGS=..." declaration.

您用每个“CFLAGS=…”声明来覆盖它们。

Moreover, it should be CXXFLAGS, not CFLAGS. CFLAGS is for C applications.

此外，它应该是CXXFLAGS，而不是CFLAGS。CFLAGS用于C应用程序。

As @Florian Sowade said, you could use CFLAGS += -O3 -std.... (or CXXFLAGS..), so that users can provide their own flags when executing make.

作为@Florian Sowade说,您可以使用CFLAGS + = o3化....(或CXXFLAGS.)，以便用户在执行时可以提供自己的标志。

#2

You can keep it in multiple lines, but you probably want to append, not to assign:

您可以将它保持在多行中，但是您可能想要追加，而不是分配:

# e.g.
CFLAGS  += -O3
CFLAGS  += -std=c++0x
CFLAGS  += -pg -D_DEBUG -g -c -Wall

#3

Where did you get that mess from? That makefile was wrong long before you modified it for C++11.

你从哪里弄来的?在修改c++ 11之前，这个makefile是错误的。

Let's start with the first line:

让我们从第一行开始:

MACHINE = $(shell echo `uname -s`-`uname -m` | sed "s/ //g")

Try running the command echo `uname -s`-`uname -m` and you'll see if has no spaces in anyway, so what's the point in the sed command?

试着运行这个命令echo ' uname -s ' - ' uname -m '，然后你会看到是否没有空格，那么sed命令的要点是什么?

Maybe you want this:

也许你想要这样的:

MACHINE = $(shell uname -s -m | sed "s/ /-/g")

That only runs two processes (uname and sed) not four (two unames, echo and sed)

它只运行两个进程(uname和sed)而不是四个进程(两个unames, echo和sed)

If you're using GNU make it should be

如果你使用GNU，那就应该是。

MACHINE := $(shell uname -s -m | sed "s/ /-/g")

So it's only run once.

所以它只运行一次。

CCC     = CC

What is CC?

CC是什么?

CCC     = g++

Oh, it doesn't matter, you've replaced the value anyway. The conventional make variable for the C++ compiler is CXX

哦，没关系，反正你已经换掉了。c++编译器的常规make变量是CXX。

CFLAGS  = -O3
CFLAGS  = -std=c++0x
CFLAGS  = -pg -D_DEBUG -g -c -Wall

As others have pointed out, you set CFLAGS, then set it to something different, then to something different. Only the last value will be kept.

正如其他人指出的那样，您设置了CFLAGS，然后将其设置为不同的东西，然后将其设置为不同的东西。只保留最后一个值。

LFLAGS  = -O
LFLAGS  = -pg -g

Same here, and what is LFLAGS? Do you mean LDFLAGS?

这里也一样，什么是LFLAGS?你是说LDFLAGS吗?

A good way to debug makefiles is to create a target to print out the variables you are setting, to check they have the values you expect:

调试makefile的一个好方法是创建一个目标来打印您正在设置的变量，检查它们是否有您期望的值:

print-vars:
        echo CFLAGS is $(CFLAGS)
        echo LDFLAGS is $(LDFLAGS)

#1