如何集中UIView的子视图(How to center a subview of UIView)

 Microsoft CRT实现了C11附录K中描述的安全库增强功能。这是规范性的，但不是强制性的。 在K.3.5.2.1节中描述了fopen_s（）。 CERT研究所规则FIO06-C也包括在内 。 
 
 问题在于fopen（）从简单的时候开始，程序员仍然可以假定他们的程序是唯一操纵文件的程序。 一个从未如此假设的假设。 它没有办法描述如何限制其他进程访问文件，CRT实现传统上在不拒绝任何访问的情况下打开文件。 非标准替代方法已被用于解决这个问题，如_fsopen() 。 
 
 如果文件打开写入，这会产生后果，另一个进程也可以打开该文件进行写入，并且文件内容将被无望破坏。 如果在另一个进程正在写入文件时打开文件进行读取，则文件内容的视图是不可预知的。 
 
 fopen_s（）通过拒绝所有访问来解决这些问题，如果打开文件进行写入，并且只有在打开文件读取文件时才允许读取访问。 

The Microsoft CRT implements the secure library enhancements described in C11 Annex K. Which is normative but not mandatory. fopen_s() is described in section K.3.5.2.1. Also covered by rule FIO06-C of the CERT institute.
 
At issue is that fopen() dates from simpler times when programmers could still assume that their program was the only one manipulating files. An assumption that has never really been true. It does not have a way to describe how access to the file by other processes is limited, CRT implementations traditionally opened the file without denying any access. Non-standard alternatives have been used to fix this problem, like _fsopen().
 
This has consequences if the file is opened for writing, another process can also open the file for writing and the file content will be hopelessly corrupted. If the file is opened for reading while another process is writing to it then the view of the file content is unpredictable.
 
fopen_s() solves these problems by denying all access if the file is opened for writing and only allowing read access when the file is opened for reading.