Why, in Elementary OS Freya, if a file written via the write (C) function with the O_CREAT flag is saved, it cannot be accessed?

Question

linux

A file saved in this way cannot be opened or copied, it can only be deleted. This is fixed by changing the access attributes, but how do you make such files available by default? In the Luna version, I did not encounter this.

Answer 1

Maybe you need mode_t umask(mode_t creationMask);