在POSIX _POSIX_VDISABLE 值中如果为-1,则所有终端设备文件的特殊字符都没有禁用字符;否则该值是禁用字符值..
可以请任何人帮助我理解这一点。我无法理解这个的确切含义。
请
最佳答案
如果您查看 definition of special characters ,那应该意味着(thre '-1' 值),所有这些特殊字符都处于事件状态:
In canonical input, the terminal driver recognizes a number of special characters which perform various control functions.
These include theERASE
character (usually DEL) for editing input, and other editing characters.
The INTR character (normally Ctrl-c) for sending aSIGINT
signal, and other signal-raising characters, may be available in either canonical or noncanonical input mode.
你有很多这样的特殊角色:
已经提出了一个问题,看看 such a value was portable (确实总是编译)是否在 1997 年:
The wording in section 2.9.4:
If any of the constants in Table 2-11 are defined to have value -1 in the header ....
can suggest, on casual reading, code like the following to minimize size and optimize efficiency for each implementation:
#ifdef _POSIX_VDISABLE
#if _POSIX_VDISABLE == -1
/* code that assumes no vdisable capability */
#else
/* code that assumes vdisable capability */
#endif
#else
/* code that uses pathconf() to determine vdisable capability */
#endif
interpretation #34 表明它会。
By using these values at COMPILE-TIME, a portable POSIX.1 application can avoid loading all pathconf() related code associated with a symbol in Table 2-11 when the symbol is defined.
关于posix - 如果 _POSIX_VDISABLE 值为 -1 会怎样?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/2891425/