軟體是怎麼關閉的

1樓：

一般來說，退出程序是通過 exit() 來進行的，這種「主動退出」包括正常退出 exit(EXIT_SUCCESS) 和非正常退出（崩潰是其中之一） exit(EXIT_FAILURE)。exit() 對應系統呼叫 exit 和 _exit，這種退出會釋放程序占用的資源（_exit不會清理 I/O 緩衝）。

The exit operation typically performs clean-up operations within the process space before returning control back to the operating system. Some systems and programming languages allow user subroutines to be registered so that they are invoked at program termination before the process actually terminates for good. As the final step of termination, a primitive system exit call is invoked, informing the operating system that the process has terminated and allows it to reclaim the resources used by the process.

It is sometimes possible to bypass the usual cleanup; C99 offers the _exit() function which terminates the current process without any extra program clean-up. This may be used, for example, in a fork-exec routine when the exec

call fails to replace the child process; calling atexit routines would erroneously release resources belonging to the parent. 先理解一下訊號的概念：A signal is an asynchronous notification sent to a process or to a specific thread within the same process in order to notify it of an event that occurred.

乙個程式在執行的時候，你可以發各種訊號給這個程序，程序對這個訊號做出響應。比如 CTRL+C，實際上對這個程序傳送了乙個訊號（SIGINT），在預設的情況下該程序會終止。但是，如果你寫了特定的 signal handler，那麼就可以修改這個預設行為。

用於"殺死"其他程序的命令 kill 實際上是乙個程式，其功能是傳送訊號。

The kill utility sends a signal to the processes specified by the pid op-

erands.

該程式會內部會呼叫 system call 的 kill 來發起真正訊號傳遞。signal(7) - Linux manual page

//kill -- send signal to a process

//The kill() function sends the signal specified by sig to pid, a process

or a group of processes.

intkill(pid_t pid, int sig);

kill 預設傳送 SIGTERM 訊號，而 kill -9 實際上是傳送了 SIGKILL 訊號。這些訊號中只有 SIGKILL 和 SIGSTOP 不可以被截獲，這兩個命令由核心處理。

$ kill -l

HUP INT QUIT ILL TRAP ABRT EMT FPE KILL BUS SEGV SYS PIPE ALRM TERM URG STOP TSTP CONT CHLD TTIN TTOU IO XCPU XFSZ VTALRM PROF WINCH INFO USR1 USR2

軟體是怎麼關閉的

怎麼關閉「我」？

怎麼看待南苑機場關閉？

QQ的6 5 5的QQ看點怎麼關閉啊？

其他用戶還看了：