当我使用g ++编译-pg标志时，gmon.out不会被创建 [英] gmon.out isn't created when I compile with -pg flag with g++

问题描述

我正在使用Mac OSX 10.8.5版本（Mountain Lion？）。

main.cpp：

  #include< iostream> 
 
 int main（）
 {
 std :: cout<< Hello world！<< std :: endl; 
 std :: cout<< 再见的世界！<< std :: endl; 
返回0; 
} 
  

我试图让gprof在我的电脑上工作。如手册所示，我输入以下内容两行代码到我的终端：

  g ++ -g -pg main.cpp -o a.out 
 ./a .out 
  

然而，这并不会像它应该生成的gmon.out文件一样。当我尝试在终端上输入gprof时，它说：

  gprof：无法打开：gmon.out（No这样的文件或目录）
  

由于gmon.out不存在

关于我在做什么的任何想法都是错误的？

编辑：其他一些可能有用的东西：

- 我有一个类似OS X版本的朋友（我可以稍后再问他确认），和g ++和gprof完全相同的版本能够使用gprof正如我已经概述的那样。

- 我使用的是旧版本的g ++，但是我在线阅读过更新到新版本并没有帮助...

-a.out完美地工作，它打印出Hello world！和再见的世界！。我也尝试过用更复杂的C ++程序和几个类，它仍然有同样的问题。一切正常，编译和运行正常，但没有产生gmon.out文件。

解决方案

您必须认识到，OS X / MacOS不会在系统上默认提供GNU GCC。

请注意以下命令的输出：

  ls -la / usr / bin / g ++ / usr / bin / clang ++ 
  

这些可执行文件看起来相同（实际上，它们看起来不一样，但不知何故文件大小是一样的！）

据我所知，clang不支持gprof输出的生成。尽管可能会引起混淆，但是 gcc 程序将运行clang。

我建议尝试使用自制软件在OS X / MacOS上安装GCC。你确实要小心它的安装方式等，以便你知道哪个命令对应哪个编译器。

I'm running on Mac OSX, version 10.8.5 (Mountain Lion?). I have the following simple C++ code.

main.cpp:

#include <iostream>

int main ()
{
    std::cout << "Hello world!"<<std::endl;
    std::cout << "Goodbye world!"<<std::endl;
    return 0;
}

I'm trying to get gprof to work on my computer. As the manual suggests, I enter the following two lines into my terminal:

g++ -g -pg main.cpp -o a.out 
./a.out

However this does not generate a gmon.out file as it is supposed to. When I try typing "gprof" in the terminal, it says:

gprof: can't open: gmon.out (No such file or directory)

which is to be expected since gmon.out isn't there...

Any ideas on what I'm doing wrong?

EDIT: Some other things that may help:

-My friend, who has a similar OS X version (I can ask him later to confirm), and the exact same versions of g++ and gprof, was able to use gprof successfully as I have outlined.

-I'm using an older version of g++ but I have read online that updating to a newer version didn't help...

-a.out works perfectly, it prints out "Hello world!" and "Goodbye world!". I also tried this with a more complex C++ program with several classes and it still has the same problem. Everything compiles and runs normally but no gmon.out file is produced.

解决方案

You have to realize that OS X/MacOS does not provide GNU GCC on the system by default.

Note the output of this command:

ls -la /usr/bin/g++ /usr/bin/clang++

These executables look identical. (Actually! It looks like they are different, but somehow the filesize is identical!)

As far as I can tell, clang doesn't support the production of gprof output. As confusing as it may be, the gcc program will run clang.

I would recommend trying to use homebrew to install GCC on OS X/MacOS. You do want to be careful about how it gets installed, etc., so that you know which command corresponds to which compiler.

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