Problems with Python output buffers

Source: Internet
Author: User

Encountered the problem, a piece of code, print in front, log in the post, look at the log in the logs instead of the front. is a problem with the Python output buffer.

The python output buffer is up to 4k before writing to the file unless the cache is disabled or the output is forced or the program ends. Intermediate CTRL + C interrupts will lose some output.

#!/usr/bin/python#Coding=utf-8" "pause 1s output" "Import TimedefPrintstar (n): forIinchrange (n):Print " * ", Time.sleep (1)if __name__=='__main__': Printstar (10)

Wait for 10s output once:

* * * * * * * * * *

#!/usr/bin/python#Coding=utf-8" "pause 1s output" "Import TimeImportSYSdefPrintstar (n): forIinchrange (n):Print " * ", Sys.stdout.flush () Time.sleep (1)if __name__=='__main__': Printstar (10)

The output is one second.

The Python program stdout output to a buffer, wait until the buffer is full or the script ends and then output, and the stderr does not output to the buffer first. Print calls Sys.stdout's Write method.

The solution:

1, run-time plus-u parameters, such as# python -u 

2. Add the Sys.stdout.flush () function after each print that does not buffer

3. Add Environment variablesPYTHONUNBUFFERED=1

Problems with Python output buffers

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