什么是Linux中/ bash程序返回值的有效范围? [英] What is the valid range for program return value in Linux/bash?
问题描述
我有一个C程序返回一个整数值。我很惊讶地发现,从shell提示符检查返回值时,我得到的数值模256。
/ * * prog.c中/
INT主(...){返回257; }
-
> ./prog.e
>回声$?
1
- 为什么我不能看到整个整数?
- 哪里是这种行为记录?
- 我怎样才能得到整个32位值到shell?
当程序退出时,它可以返回到父进程的少量信息,有关终止的原因,使用退出状态。这是介于0和255之间的值,该退出的过程传递作为参数退出。
块引用><一个href=\"http://www.gnu.org/s/hello/manual/libc/Exit-Status.html\">http://www.gnu.org/s/hello/manual/libc/Exit-Status.html
或者
http://en.wikipedia.org/wiki/Exit_status
从POSIX回报codeS来了,C返回codeS各自的谷歌搜索。
I have a C program which returns an integer value. I was surprised to find out that when examining the return value from the shell prompt I get the value modulo 256.
/* prog.c */ int main(...) { return 257; }
--
> ./prog.e > echo $? 1
- Why don't I see the whole integer?
- Where is this behavior documented?
- How can I get the whole 32-bit value to the shell?
解决方案When a program exits, it can return to the parent process a small amount of information about the cause of termination, using the exit status. This is a value between 0 and 255 that the exiting process passes as an argument to exit.
http://www.gnu.org/s/hello/manual/libc/Exit-Status.html
alternatively:
http://en.wikipedia.org/wiki/Exit_status
came from "posix return codes" and "c return codes" respective Google searches.
这篇关于什么是Linux中/ bash程序返回值的有效范围?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!