std::filesystem::perm_options
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< cpp | filesystem
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Feature test macros (C++20)
Concepts library (C++20)
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Ranges library (C++20)
Filesystem library (C++17)
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Execution control library (C++26)
Defined in header
<filesystem>
enum class perm_options {
(since C++17)
replace = /* unspecified */,
add = /* unspecified */,
remove = /* unspecified */,
nofollow = /* unspecified */
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).
[edit] Member constants
At most one of add, remove, replace may be present, otherwise the behavior of the permissions function is undefined.
Enumerator
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
[edit] Example
Run this code
#include <filesystem> #include <fstream> #include <iostream> 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--