File Permissions

Permission Functions

We have two major functions related to file permissions:

• std::filesystem::status() and
• std::filesystem::permissions()

The first one returns file_status which contains information about the file type and also its permissions.

And you can use the second function to modify the file permissions. For example, to change a file to be read-only.

std::filesystem::perms

File permissions - std::filesystem::perms - it’s an enum class that represents the following values:

Name	Value (octal)	POSIX macro	Notes
none	0000		There are no permissions set for the file
owner_read	0400	S_IRUSR	Read permission, owner
owner_write	0200	S_IWUSR	Write permission, owner
owner_exec	0100	S_IXUSR	Execute/search permission, owner
owner_all	0700	S_IRWXU	Read, write, execute/search for owner
group_read	0040	S_IRGRP	Read permission, group
group_write	0020	S_IWGRP	Write permission, group
group_exec	0010	S_IXGRP	Execute/search permission, group
group_all	0070	S_IRWXG	Read, write, execute/search by group
others_read	0004	S_IROTH	Read permission, others
others_write	0002	S_IWOTH	Write permission, others
others_exec	0001	S_IXOTH	Execute/search permission, others
others_all	0007	S_IRWXO	Read, write, execute/search for others
all	0777		owner_all | group_all | others_all
set_uid	04000	S_ISUID	Set-user-ID on execution
set_gid	02000	S_ISGID	Set-group-ID on execution
sticky_bit	01000	S_ISVTX	Operating system dependent
mask	07777		all | set_uid | set_gid | sticky_bit
unknown	0xFFFF		The permissions are not known