Is there a standard way to change file permissions?

[Gavin Deane]

Hello C people.
I couldn't find this in the FAQ, so ...

The remove function returns non-zero if it fails. My compiler
documentation also says that if remove failed because the file is
read-only, errno is set to EACCESS.

Question 1
Is that value and meaning of errno standard?

Question 2
If so, is there a standard way of changing the file's permissions so
it is not read only and I can remove it? I suspect not but I'd like to
be sure.

TIA
GJD