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 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 <bitset>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
void demo_perms(fs::perms p)
{
std::cout << ((p & fs::perms::owner_read) != fs::perms::none ? "r" : "-")
<< ((p & fs::perms::owner_write) != fs::perms::none ? "w" : "-")
<< ((p & fs::perms::owner_exec) != fs::perms::none ? "x" : "-")
<< ((p & fs::perms::group_read) != fs::perms::none ? "r" : "-")
<< ((p & fs::perms::group_write) != fs::perms::none ? "w" : "-")
<< ((p & fs::perms::group_exec) != fs::perms::none ? "x" : "-")
<< ((p & fs::perms::others_read) != fs::perms::none ? "r" : "-")
<< ((p & fs::perms::others_write) != fs::perms::none ? "w" : "-")
<< ((p & fs::perms::others_exec) != fs::perms::none ? "x" : "-")
<< '\n';
}
int main()
{
std::ofstream("test.txt"); // create file
std::cout << "Created file with permissions: ";
demo_perms(fs::status("test.txt").permissions());
fs::permissions("test.txt",
fs::perms::owner_all | fs::perms::group_all,
fs::perm_options::add);
std::cout << "After adding o+rwx and g+rwx: ";
demo_perms(fs::status("test.txt").permissions());
fs::remove("test.txt");
}Possible output:
Created file with permissions: rw-r--r-- After adding o+rwx and g+wrx: rwxrwxr--
|
(C++17) | modifies file access permissions (function) |
|
(C++17) | identifies file system permissions (enum) |
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