atexit(3)的手册页说明如下：
POSIX.1-2001 says that the result of calling
exit(3)more than once (i.e.,callingexit(3)within a function registered usingatexit()) is undefined. On some systems (but not Linux),this can result in an infinite recursion; portable programs should not invokeexit(3)inside a function registered usingatexit().
但是,我有兴趣在我的程序的终结器中修改退出代码.我设法做到这一点的唯一方法是从我的终结函数中调用exit(),但是手册页明确地警告了这一点.
解决方法
_exit().
在手册页的Notes部分中：
The function
_exit()is likeexit(),but does not call any functions registered withatexit()oron_exit().
这应该避免POSIX规范中警告的“递归”问题.如果你能以某种方式保证你的“退出代码更改”退出处理程序最后运行,这应该完美地工作,模拟Notes中列出的警告：
Whether it flushes standard I/O buffers and removes temporary files created with
tmpfile(3)is implementation-dependent. On the other hand,_exit()does close open file descriptors,and this may cause an unknown delay,waiting for pending output to finish. If the delay is undesired,it may be useful to call functions liketcflush(3)before calling_exit(). Whether any pending I/O is canceled,and which pending I/O may be canceled upon_exit(),is implementation-dependent.
