Defined in header <filesystem> | ||
|---|---|---|
enum class perm_options {
replace = /* unspecified */,
add = /* unspecified */,
remove = /* unspecified */,
nofollow = /* unspecified */
};
| (since C++17) |
This type represents available options that control the behavior of the function std::filesystem::permissions().
perm_options satisfies the requirements of BitmaskType (which means the bitwise operators operator&, operator|, operator^, operator~, operator&=, operator|=, and operator^= are defined for this type).
At most one of add, remove, replace may be present, otherwise the behavior of the permissions function is undefined.
| Member constant | Meaning |
|---|---|
replace | Permissions will be completely replaced by the argument to permissions() (default behavior) |
add | permissions will be replaced by the bitwise OR of the argument and the current permissions |
remove | permissions will be replaced by the bitwise AND of the negated argument and current permissions |
nofollow | permissions will be changed on the symlink itself, rather than on the file it resolves to |
#include <fstream>
#include <iostream>
#include <filesystem>
void demo_perms(std::filesystem::perms p)
{
using std::filesystem::perms;
auto show = [=](char op, perms perm)
{
std::cout << (perms::none == (perm & p) ? '-' : op);
};
show('r', perms::owner_read);
show('w', perms::owner_write);
show('x', perms::owner_exec);
show('r', perms::group_read);
show('w', perms::group_write);
show('x', perms::group_exec);
show('r', perms::others_read);
show('w', perms::others_write);
show('x', perms::others_exec);
std::cout << '\n';
}
int main()
{
std::ofstream("test.txt"); // create file
std::cout << "Created file with permissions: ";
demo_perms(std::filesystem::status("test.txt").permissions());
std::filesystem::permissions(
"test.txt",
std::filesystem::perms::owner_all | std::filesystem::perms::group_all,
std::filesystem::perm_options::add
);
std::cout << "After adding u+rwx and g+rwx: ";
demo_perms(std::filesystem::status("test.txt").permissions());
std::filesystem::remove("test.txt");
}Possible output:
Created file with permissions: rw-r--r-- After adding u+rwx and g+wrx: rwxrwxr--
|
(C++17) | modifies file access permissions (function) |
|
(C++17) | identifies file system permissions (enum) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/filesystem/perm_options