std::filesystem::perm_options
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Cpp/docs/latest/filesystem/perm options
std::filesystem::perm_options
Defined in header <filesystem>
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(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).
Member constants
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 |
Example
#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--
See also
(C++17) |
modifies file access permissions (function) |
(C++17) |
identifies file system permissions (enum) |
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