JVM:如何定义Java可执行文件的退出代码? [英] JVM: how are exit codes of the java executable defined?

问题描述

我正在寻找java可执行文件的可能退出代码的定义:

I'm looking for a definition of possible exit codes of the java executable:

(如何确定退出代码是执行的Java进程还是虚拟机本身?)

示例:在Windows上，java -badoption返回1； java Main且Main是有效的类，也可能会返回1.

Example: On Windows, java -badoption returns 1; java Main with Main being a valid class may return 1 as well.

我可以使用任何VM选项使退出代码更有意义吗?例如.区分两种退出代码?

Are there any VM options I could use to make exit codes more meaningful? E.g. to distinguish between both types of exit codes?

如果我知道退出代码不是来自Java进程(仅返回0)，那么非零退出代码是什么意思?

If I know that the exit code is not from my Java process (which only returns 0), what do non-zero exit codes mean?

在Windows上，我经常看到-1和1.由于这些是通过自动错误报告工具报告的，因此我看不到任何错误消息.我只有退出代码，需要对其进行解释.

On Windows, I'm frequently seeing -1 and 1. As these are reported through an automated bug-reporting facility, I can't see any error messages. I only have the exit code and need to interpret it.

退出代码是否取决于平台?

推荐答案

退出代码的含义(通常)

ISO/IEC 9899(编程语言:C)，ISO/IEC 9945(IEEE 1003，POSIX)

没有专门针对Java/JVM定义的内容.这些退出代码的含义由ISO/IEC 9899(编程语言:C，例如7.20.4.3)定义.

Meaning of Exit Codes (in general)

ISO/IEC 9899 (Programming Languages: C), ISO/IEC 9945 (IEEE 1003, POSIX)

There is nothing which is specifically defined for Java / JVM. The meaning of these exit codes is defined by ISO/IEC 9899 (Programming Languages: C, for example 7.20.4.3 The exit function of ISO/IEC 9899:TC3), ISO/IEC 9945 (IEEE 1003, POSIX) and similar specifications, and it's always like this:

• 0表示成功
• 其他任何值均表示失败

shell环境(sh，bash，cmd.exe，make等)使用它来确定程序是成功退出(0)还是出错(不是0).

This is used by shell environments (sh, bash, cmd.exe, make etc. etc.) to determine whether a program exited successfully (0) or there was an error (not 0).

强烈建议仅使用0表示成功.使用0以外的值获得成功的程序会使Shell脚本，Makefile等文件的编写者感到头疼.

It is strongly recommended to use only 0 for success. Programs which use values other than 0 for success cause headache to the authors of shell scripts, Makefiles and alike.

由各个程序来定义不同故障值的其他语义.但是，我认为-1并不是一个好主意.最好的办法是使用EXIT_SUCCESS和EXIT_FAILURE，但是，<stdlib.h>中的这些定义在Java中没有相应的对应项. ISO/IEC 9899:2011没有描述应如何定义EXIT_FAILURE和EXIT_SUCCESS.但是，它将0定义为具有与EXIT_SUCCESS相同的语义，并且我不知道任何系统除以下功能外还可以执行其他操作，因此这是Java程序员可以假定的最好的事情:

It's up to the individual program to define additional semantics of different failure values. However, I think -1 is not such a good idea. The best thing would be to use EXIT_SUCCESS and EXIT_FAILURE, however, these definitions from <stdlib.h> have no corresponding counterparts in Java. ISO/IEC 9899:2011 does not describe how EXIT_FAILURE and EXIT_SUCCESS should be defined. However, it defines 0 as having the same semantics as EXIT_SUCCESS, and I do not know of any system which does something else than the following, which therefore is the best thing a Java programmer can assume:

#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1

因此，如果要区分不同类型的故障很重要，我将使用0表示成功，使用1表示失败，并使用不同于1的值.一个很好的例子是grep命令.从其手册页(GNU grep):

So, I'd use 0 for success, 1 for failure, and values distinct from 1 if it is important to differentiate between different types of failure. A good example is the grep command. From its man page (GNU grep):

退出状态 如果找到选定的行，则退出状态为0；如果未找到，则退出状态为1.如果发生错误，则退出状态为2.(注意:POSIX错误处理代码应检查'2'或更大.)

EXIT STATUS The exit status is 0 if selected lines are found, and 1 if not found. If an error occurred the exit status is 2. (Note: POSIX error handling code should check for '2' or greater.)

我不使用-1，因为它会设置所有位，并且根据环境的不同，-1可能实际上会意外地生成附加的伪造信息，例如声称信号已发出等.实际上，为了便于移植，除非您真的真的很清楚自己在做什么，否则退出代码应在[0..127]范围内. 例如，在大多数POSIX系统上，退出代码将被截断为8位，并且高于127的退出代码的语义是退出是由信号引起的.

I'd not use -1 because it sets all bits, and depending on the environment, -1 might actually accidentally generate additonal bogus information, like claiming that signals were raised and alike. Actually, to be portable, the exit code should be within the range [0..127], unless you really really really know what you're doing. For example, on most POSIX systems, the exit code will be truncated to 8 bits, and the semantics of an exit code above 127 is that the exit was caused by a signal.

BSD尝试提供更多退出代码，这些代码可以在/usr/include/sysexits.h中使用(

BSD has tried to supply a few more exit codes, which are available in /usr/include/sysexits.h (man page). They are like this:

• 64:命令行使用错误
• 65:数据格式错误
• 66:无法打开输入
• 67:收件人未知
• 68:主机名未知
• 69:服务不可用
• 70:内部软件错误
• 71:系统错误(即无法分叉)
• 72:缺少重要的操作系统文件
• 73:无法创建(用户)输出文件
• 74:输入/输出错误
• 75:临时失败；邀请用户重试
• 76:协议中的远程错误
• 77:权限被拒绝
• 78:配置错误

• 64: command line usage error
• 65: data format error
• 66: cannot open input
• 67: addressee unknown
• 68: host name unknown
• 69: service unavailable
• 70: internal software error
• 71: system error (i.e. can't fork)
• 72: critical OS file missing
• 73: can't create (user) output file
• 74: input/output error
• 75: temp failure; user is invited to retry
• 76: remote error in protocol
• 77: permission denied
• 78: configuration error

在没有其他有意义的标准的情况下，我认为我们可以做的最好的事情就是使用它们.

In the absence of any other meaningful standard, I think the best thing we can do is use them.

在UNIX上，您可以通过屏蔽退出值的低7位(减128)来获得信号，在大多数shell中，可以使用$?来查询该值.

On UNIX, you can obtain the signal by masking out the lower 7 bits (subtract 128) from the exit value, which in most shells can be queried using $?.

• SIGTERM-> VM:143 SIGTERM
• SIGSEGV-> VM:134 SIGABRT(因为VM处理SIGSEGV来写入hs_err文件，然后调用abort()).

• SIGTERM -> VM: 143 SIGTERM
• SIGSEGV -> VM: 134 SIGABRT (because the VM handles SIGSEGV to write the hs_err file and then calls abort()).

与普通"程序的比较:

• SIGSEGV->编:139 SIGSEGV

• SIGSEGV -> prog: 139 SIGSEGV

未为JVM明确指定此行为，它只是POSIX环境中程序的正常预期行为.鉴于JVM希望自己处理SIGSEGV，并且编写比普通核心文件更具体的崩溃转储，甚至甚至期望SIGABRT代替SIGSEGV.

This behavior is not explicitly specified for the JVM, it is just the normal expected behavior of programs in a POSIX environment. Even the SIGABRT instead of SIGSEGV is more or less expected, given that the JVM wants to handle SIGSEGV on its own, writing a more specific crash dump than a normal core file.

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