The getmode function returns a copy of the file permission bits mode as altered by the values pointed to by set. While only the mode bits are altered, other parts of the file mode may be examined.
The setmode function takes an absolute (octal) or symbolic value, as described in chmod(1), as an argument and returns a pointer to mode values to be supplied to getmode. Because some of the symbolic values are relative to the file creation mask, setmode may call umask(2). If this occurs, the file creation mask will be restored before setmode returns. If the calling program changes the value of its file creation mask after calling setmode, setmode must be called again if getmode is to modify future file modes correctly.
If the mode passed to setmode is invalid or if memory cannot be allocated for the return value, setmode returns NULL.
The value returned from setmode is obtained from malloc and should be returned to the system with free when the program is done with it, generally after a call to getmode.
The setmode function may fail and set errno for any of the errors specified for the library routine malloc(3).
chmod(1), stat(2), umask(2), malloc(3)