blocks|key|1673314|text|似乎每个人都在试图改进你的代码，以便在你的代码中抛出异常，而没有人尝试你提出的实际问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1673315|这是因为这是不可能的。如果抛出异常的代码只以二进制形式出现(例如，在LIB或DLL文件中)，那么行号就没有了，并且没有办法将对象连接到源代码中的一行。|1673316|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

It seems everyone is trying to improve your code to throw exceptions in your code, and no one is attempting the actual question you asked.

Which is because it can't be done. If the code that's throwing the exception is only presented in binary form (e.g. in a LIB or DLL file), then the line number is gone, and there's no way to connect the object to to a line in the source code.

blocks|key|1458093|text|更好的解决方案是使用自定义类和宏。:-)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1458094|#include+<iostream>
#include+<sstream>
#include+<stdexcept>
#include+<string>

class+my_exception+:+public+std::runtime_error+{
++++std::string+msg;
public:
++++my_exception(const+std::string+&arg,+const+char+*file,+int+line)+:
++++std::runtime_error(arg)+{
++++++++std::ostringstream+o;
++++++++o+<<+file+<<+":"+<<+line+<<+":+"+<<+arg;
++++++++msg+=+o.str();
++++}
++++~my_exception()+throw()+{}
++++const+char+*what()+const+throw()+{
++++++++return+msg.c_str();
++++}
};
#define+throw_line(arg)+throw+my_exception(arg,+__FILE__,+__LINE__);

void+f()+{
++++throw_line("Oh+no!");
}

int+main()+{
++++try+{
++++++++f();
++++}
++++catch+(const+std::runtime_error+&ex)+{
++++++++std::cout+<<+ex.what()+<<+std::endl;
++++}
}|code-block|syntax|javascript|1458095|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

A better solution is to use a custom class and a macro. :-)

<pre><code>#include &lt;iostream&gt;
#include &lt;sstream&gt;
#include &lt;stdexcept&gt;
#include &lt;string&gt;

class my_exception : public std::runtime_error {
 std::string msg;
public:
 my_exception(const std::string &amp;arg, const char *file, int line) :
 std::runtime_error(arg) {
 std::ostringstream o;
 o &lt;&lt; file &lt;&lt; ":" &lt;&lt; line &lt;&lt; ": " &lt;&lt; arg;
 msg = o.str();
 }
 ~my_exception() throw() {}
 const char *what() const throw() {
 return msg.c_str();
 }
};
#define throw_line(arg) throw my_exception(arg, __FILE__, __LINE__);

void f() {
 throw_line("Oh no!");
}

int main() {
 try {
 f();
 }
 catch (const std::runtime_error &amp;ex) {
 std::cout &lt;&lt; ex.what() &lt;&lt; std::endl;
 }
}
</code></pre>

blocks|key|1673196|text|最简单的解决方案是使用宏：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1673197|#define+throw_line(msg)+\
++++throw+std::exception(msg+"+"+__FILE__+":"+__LINE__)

void+f()+{
++++throw_line("Oh+no!");
}|code-block|syntax|javascript|1673198|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The simplest solution is to use a macro:

<pre><code>#define throw_line(msg) \
 throw std::exception(msg " " __FILE__ ":" __LINE__)

void f() {
 throw_line("Oh no!");
}
</code></pre>

blocks|key|1673414|text|到目前为止还没有人提到boost。如果您使用的是boost+c%2B%2B库，那么它们确实提供了一些不错的默认异常：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1673415|#include+<boost/exception/diagnostic_information.hpp>
#include+<exception>
#include+<iostream>

struct+MyException+:+std::exception+{};

int+main()
{
++try
++{
++++BOOST_THROW_EXCEPTION(MyException());
++}
++catch+(MyException+&ex)
++{
++++std::cerr+<<+"Unexpected+exception,+diagnostic+information+follows:\n"
++++++++++++++<<+boost::current_exception_diagnostic_information();
++}
++return+0;
}|code-block|syntax|javascript|1673416|然后你可能会得到类似这样的结果：|1673417|Unexpected+exception,+diagnostic+information+follows:
main.cpp(10):+Throw+in+function+int+main()
Dynamic+exception+type:+boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<MyException>+>
std::exception::what:+std::exception|1673418|文档：https://www.boost.org/doc/libs/1_63_0/libs/exception/doc/diagnostic_information.html|offset|length|1673419|entityMap|0|LINK|mutability|MUTABLE|url|https://www.boost.org/doc/libs/1_63_0/libs/exception/doc/diagnostic_information.html^0|0|0|0|0|3|2C|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

No one mentioned boost so far. If you're using boost c++ libraries they do come with some nice exception defaults for this:

<pre><code>#include &lt;boost/exception/diagnostic_information.hpp&gt;
#include &lt;exception&gt;
#include &lt;iostream&gt;

struct MyException : std::exception {};

int main()
{
 try
 {
 BOOST_THROW_EXCEPTION(MyException());
 }
 catch (MyException &amp;ex)
 {
 std::cerr &lt;&lt; "Unexpected exception, diagnostic information follows:\n"
 &lt;&lt; boost::current_exception_diagnostic_information();
 }
 return 0;
}
</code></pre>

And then you might get something like:

<pre><code>Unexpected exception, diagnostic information follows:
main.cpp(10): Throw in function int main()
Dynamic exception type: boost::exception_detail::clone_impl&lt;boost::exception_detail::error_info_injector&lt;MyException&gt; &gt;
std::exception::what: std::exception
</code></pre>

Docs: <a href="https://www.boost.org/doc/libs/1_63_0/libs/exception/doc/diagnostic_information.html" rel="nofollow noreferrer">https://www.boost.org/doc/libs/1_63_0/libs/exception/doc/diagnostic_information.html</a>

blocks|key|1458238|text|受到Frank+Krueger的回答和std::nested_exception文档的启发，我意识到您可以将Frank的回答(我已经使用了一段时间)与std::nested_exception结合起来，创建包含文件和行信息的完整错误堆栈跟踪。以我的实现为例，运行|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1458239|#include+"Thrower.h"
#include+<iostream>
//+runs+the+sample+function+above+and+prints+the+caught+exception
int+main+(+)
{
++++try+{
++++++++//+[Doing+important+stuff...]
++++++++try+{
++++++++++++std::string+s+=+"Hello,+world!";
++++++++++++try+{
++++++++++++++++int+i+=+std::stoi+(+s+);
++++++++++++}
++++++++++++catch+(+...+)+{
++++++++++++++++thrower+(+"Failed+to+convert+string+\""+%2B+s+%2B+"\"+to+an+integer!"+);
++++++++++++}
++++++++}
++++++++catch+(+Error&+e+)+{
++++++++++++thrower+(+"Failed+to+[Do+important+stuff]!"+);
++++++++}
++++}
++++catch+(+Error&+e+)+{
++++++++std::cout+<<+Error::getErrorStack+(+e+);
++++}
++++std::cin.get+(+);
}|code-block|syntax|javascript|1458240|输出|1458241|ERROR:+Failed+to+[Do+important+stuff]!
@+Location:c:\path\main.cpp;+line+33
+ERROR:+Failed+to+convert+string+"Hello,+world!"+to+an+integer!
+@+Location:c:\path\main.cpp;+line+28
++ERROR:+invalid+stoi+argument|1458242|下面是我的实现：|1458243|#include+<sstream>
#include+<stdexcept>
#include+<regex>

class+Error+:+public+std::runtime_error
{
++++public:
++++Error+(+const+std::string+&arg,+const+char+*file,+int+line+)+:+std::runtime_error(+arg+)
++++{
++++++++loc+=+std::string+(+file+)+%2B+";+line+"+%2B+std::to_string+(+line+);
++++++++std::ostringstream+out;
++++++++out+<<+arg+<<+"\n@+Location:"+<<+loc;
++++++++msg+=+out.str(+);
++++++++bareMsg+=+arg;++++++
++++}
++++~Error(+)+throw()+{}

++++const+char+*+what(+)+const+throw()
++++{
++++++++return+msg.c_str(+);
++++}
++++std::string+whatBare(+)+const+throw()
++++{
++++++++return+bareMsg;
++++}
++++std::string+whatLoc+(+)+const+throw(+)
++++{
++++++++return+loc;
++++}
++++static+std::string+getErrorStack+(+const+std::exception&+e,+unsigned+int+level+=+0)
++++{
++++++++std::string+msg+=+"ERROR:+"+%2B+std::string(e.what+(+));
++++++++std::regex+r+(+"\n"+);
++++++++msg+=+std::regex_replace+(+msg,+r,+"\n"%2Bstd::string+(+level,+'+'+)+);
++++++++std::string+stackMsg+=+std::string+(+level,+'+'+)+%2B+msg+%2B+"\n";
++++++++try
++++++++{
++++++++++++std::rethrow_if_nested+(+e+);
++++++++}
++++++++catch+(+const+std::exception&+e+)
++++++++{
++++++++++++stackMsg+%2B=+getErrorStack+(+e,+level+%2B+1+);
++++++++}
++++++++return+stackMsg;
++++}
++++private:
++++++++std::string+msg;
++++++++std::string+bareMsg;
++++++++std::string+loc;
};

//+(Important+modification+here)
//+the+following+gives+any+throw+call+file+and+line+information.
//+throw_with_nested+makes+it+possible+to+chain+thrower+calls+and+get+a+full+error+stack+traceback
#define+thrower(arg)+std::throw_with_nested(+Error(arg,+__FILE__,+__LINE__)+)|1458244|1458245|entityMap|0|LINK|mutability|MUTABLE|url|https://en.cppreference.com/w/cpp/error/nested_exception/^0|J|L|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|F|7|13|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|14|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|15|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|16|8|@]|9|@]|C|$]]|$1|O|3|P|5|F|7|17|8|@]|9|@]|C|$G|H]]|$1|Q|3|-4|5|F|7|18|8|@]|9|@]|C|$G|H]]|$1|R|3|-4|5|6|7|19|8|@]|9|@]|C|$]]]|S|$T|$5|U|V|W|C|$X|Y]]]]

Inspired by Frank Krueger's answer and the documentation for <a href="https://en.cppreference.com/w/cpp/error/nested_exception/" rel="nofollow noreferrer" title="std::nested_exception">std::nested_exception</a>, I realized that you can combine Frank's answer, which I've been using for a while, with std::nested_exception to create a full error stack trace with file &amp; line info. For example with my implementation, running

<pre><code>#include "Thrower.h"
#include &lt;iostream&gt;
// runs the sample function above and prints the caught exception
int main ( )
{
 try {
 // [Doing important stuff...]
 try {
 std::string s = "Hello, world!";
 try {
 int i = std::stoi ( s );
 }
 catch ( ... ) {
 thrower ( "Failed to convert string \"" + s + "\" to an integer!" );
 }
 }
 catch ( Error&amp; e ) {
 thrower ( "Failed to [Do important stuff]!" );
 }
 }
 catch ( Error&amp; e ) {
 std::cout &lt;&lt; Error::getErrorStack ( e );
 }
 std::cin.get ( );
}
</code></pre>

outputs

<pre><code>ERROR: Failed to [Do important stuff]!
@ Location:c:\path\main.cpp; line 33
 ERROR: Failed to convert string "Hello, world!" to an integer!
 @ Location:c:\path\main.cpp; line 28
 ERROR: invalid stoi argument
</code></pre>

Here's my implementation:

<pre><code>#include &lt;sstream&gt;
#include &lt;stdexcept&gt;
#include &lt;regex&gt;

class Error : public std::runtime_error
{
 public:
 Error ( const std::string &amp;arg, const char *file, int line ) : std::runtime_error( arg )
 {
 loc = std::string ( file ) + "; line " + std::to_string ( line );
 std::ostringstream out;
 out &lt;&lt; arg &lt;&lt; "\n@ Location:" &lt;&lt; loc;
 msg = out.str( );
 bareMsg = arg; 
 }
 ~Error( ) throw() {}

 const char * what( ) const throw()
 {
 return msg.c_str( );
 }
 std::string whatBare( ) const throw()
 {
 return bareMsg;
 }
 std::string whatLoc ( ) const throw( )
 {
 return loc;
 }
 static std::string getErrorStack ( const std::exception&amp; e, unsigned int level = 0)
 {
 std::string msg = "ERROR: " + std::string(e.what ( ));
 std::regex r ( "\n" );
 msg = std::regex_replace ( msg, r, "\n"+std::string ( level, ' ' ) );
 std::string stackMsg = std::string ( level, ' ' ) + msg + "\n";
 try
 {
 std::rethrow_if_nested ( e );
 }
 catch ( const std::exception&amp; e )
 {
 stackMsg += getErrorStack ( e, level + 1 );
 }
 return stackMsg;
 }
 private:
 std::string msg;
 std::string bareMsg;
 std::string loc;
};

// (Important modification here)
// the following gives any throw call file and line information.
// throw_with_nested makes it possible to chain thrower calls and get a full error stack traceback
#define thrower(arg) std::throw_with_nested( Error(arg, __FILE__, __LINE__) )
</code></pre>

```

blocks|key|1673158|text|我认为堆栈跟踪应该可以让您切中要害。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1673159|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I think that a stack trace should get you to the point.

blocks|key|1458357|text|在调试模式下编译您的软件并使用valgrind运行它。它主要用于查找内存泄漏，但它也可以向您显示valgrind+--leak-check=full+/path/to/your/software中发生异常的确切位置。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1458358|entityMap^0|1C|1D|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Compile your software in debug mode and run it with valgrind. It is mainly for finding memory leaks but it can also show you the exact line of where exceptions occur <code>valgrind --leak-check=full /path/to/your/software</code>.

blocks|key|1673532|text|其他人已经建议使用宏，可能还会使用自定义类。但是如果你有一个异常层次结构，你还需要在抛出异常时指定异常类型：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1673533|#define+THROW(ExceptionType,+message)++++++++++++++++++++++++++++++++++++\
++++throw+ExceptionType(std::string(message)+%2B+"+in+"+%2B+__FILE__+%2B+':'+++\
++++++++++++++++++++++++%2B+std::to_string(__LINE__)+%2B+':'+%2B+__func__)

THROW(Error,+"An+error+occurred");|code-block|syntax|javascript|1673534|这里的假设是，所有异常都接受单个字符串参数，这并不是限制性的，因为可以将其他参数转换为字符串(例如，使用std::to_string())，并将它们连接为单个字符串。|offset|length|style|CODE|1673535|entityMap^0|0|0|1G|G|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Others have already proposed using a macro and possibly a custom class. But in case you have an exception hierarchy, you need to also specify the exception type while throwing:
<pre class="lang-cpp prettyprint-override"><code>#define THROW(ExceptionType, message) \
 throw ExceptionType(std::string(message) + &quot; in &quot; + __FILE__ + ':' \
 + std::to_string(__LINE__) + ':' + __func__)

THROW(Error, &quot;An error occurred&quot;);
</code></pre>
The assumption here is that all exceptions accept a single string argument, which is not limiting, as one can convert other arguments to strings (e.g. with <code>std::to_string()</code>) and concatenate them to a single string.

blocks|key|1458132|text|根据Frank+Krueger的建议，除了使用带有宏的自定义类来处理您自己的异常之外，您还可能有兴趣了解一下结构化异常处理机制(您是在windows下编程的，对吧？)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1458133|检查Structured+Exception+Handling+on+MSDN|offset|length|1458134|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/ms680657%2528VS.85%2529.aspx^0|0|2|11|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

Apart from using a custom class with a macro, as suggested by Frank Krueger, for your own exceptions, you might be interested in taking a look at the structured exception handling mechanism (you're programming under windows, right?) 
Check <a href="http://msdn.microsoft.com/en-us/library/ms680657%28VS.85%29.aspx" rel="nofollow noreferrer">Structured Exception Handling on MSDN</a>

If I generate an exception on my own, I can include any info into the exception: a number of code line and name of source file. Something like this:

<pre><code>throw std::exception("myFile.cpp:255");
</code></pre>

But what's with unhandled exceptions or with exceptions that were not generated by me?

How to know the exact line of code where an exception has been caused?

如果我自己生成一个异常，我可以在异常中包含任何信息:一些代码行和源文件的名称。如下所示：throw std::exception("myFile.cpp:255");但是，未处理的异常或不是由我生成的异常又有什么关系呢？

问如何知道导致异常的确切代码行？
EN

回答 9

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