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O_TRUNC Flag Behaviour

Question Text​

How does the O_TRUNC flag change the behaviour of open()?

Question Answers​

  • the previous content of the file is deleted

  • new data will be appended to the file

  • newly written data will be ignored

Feedback​

The man page provides us with unlimited wisdon:

If the file already exists and is a regular file and the access mode allows writing (i.e., is O_RDWR or O_WRONLY) it will be truncated to length 0.

Setting the length of the file to 0 is equivalent to deleting the previous content of the file.