Python os.ttyname()

Python中的os.ttyname()方法用于获取与指定的文件描述符相关联的终端设备。

文件描述符是一个小整型值，对应于一个文件或其他输入/输出资源，如管道或网络套接字。它是一个资源的抽象指示器，并作为句柄来执行各种较低级的I/O操作，如读、写、发送等。

例如:标准输入通常是值为0的文件描述符，标准输出通常是值为1的文件描述符，标准错误通常是值为2的文件描述符。这些文件描述符i. e0 (stdin)、1 (stdout)和2 (stderr)是程序使用的标准文件描述符。当前进程打开的其他文件将获得值3、4、5等等。

注意:此方法仅在UNIX平台上可用，如果指定的文件描述符不与任何终端设备关联，则会引发异常。

语法:os.ttyname(fd)

参数:

fd:文件描述符

返回类型:该方法返回一个字符串值，表示与指定的文件描述符fd关联的终端设备。

示例1

使用os.tyname()方法来获取与文件描述符相关的终端设备。

# Python program to explain os.ttyname() method  
  
# importing os module 
import os
  
  
# Standard file descriptors
# i.e 0 (stdin), 1 (stdout), and 2 (stderr)
# are used by our program 
# Get the terminal device 
# associated with these file descriptor
print("Terminal device associated with:")
print("Standard input:", os.ttyname(0))
print("Standard output:", os.ttyname(1))
print("standard error", os.ttyname(2))
  
  
# Open a new pseudo-terminal pair
# using os.openpty() method
# It will return master and slave 
# file descriptor for 
# pty ( pseudo terminal device) and
# tty ( native terminal device) respectively
master, slave = os.openpty()
  
# Get the terminal device 
# associated with these file descriptor
print("Master:", os.ttyname(master))
print("Slave:", os.ttyname(slave))

输出:

Terminal device associated with:
Standard input: /dev/pts/0
Standard output: /dev/pts/0
standard error /dev/pts/0
Master: /dev/ptmx
Slave: /dev/pts/1

示例2

如果指定的文件描述符不与任何终端设备关联

# Python program to explain os.ttyname() method  
  
# importing os module 
import os
  
  
# If the specified file descriptor
# is not associated with any 
# terminal device, then an exception
# will be raised. For example:
  
# Create a pipe using os.pipe() method
# It will return a pair of 
# file descriptors (r, w) usable for
# reading and writing, respectively.
r, w = os.pipe()
  
# Get the terminal device associated 
# with the file descriptor r or w
print(os.ttyname(r))

输出:

Traceback (most recent call last):
  File "getTerminalDevice.py", line 20, in 
    print(os.ttyname(r))
OSError: [Errno 25] Inappropriate ioctl for device

示例3

处理上述异常的方法

# Python program to explain os.ttyname() method  
  
# importing os module 
import os
  
  
# Create a pipe using os.pipe() method
# It will return a pair of 
# file descriptors (r, w) usable for
# reading and writing, respectively.
r, w = os.pipe()
  
# Method 1 
# (using exception handling technique)
# Try to get the terminal device associated 
# with the file descriptor r or w
try :
    print(os.ttyname(r)) 
except OSError as error :
    print(error)
    print("File descriptor is not associated with any terminal device")
  
  
# Method 2
# using os.isatty() method
# check first if the file descriptor w
# is associated with a tty(-like) device or not
# if it is then only get the terminal
# device associated with it
if os.isatty(w) :
    print(os.ttyname(w))
else :
    print("File descriptor is not associated with any terminal device")

输出:

[Errno 25] Inappropriate ioctl for device
File descriptor is not associated with any terminal device
File descriptor is not associated with any terminal device