It is not possible to set the sticky bit of a file when creating it. Therefore it is necessary to create the directory and then set the sticky bit by executing: mkdir(“/tmp/dir”, 0744); chmod(“/tmp/dir”, 07744). Why?

The mkdir() command is privileged, and doesn’t allow any modification to permissions

The behavior of mkdir() is undefined if anything other than permission bits is set

UNIX requires that directories be created before any non-permission bits are set

Answer:
The behavior of mkdir() is undefined if anything other than permission bits is set

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