Difference between revisions of "cpp/filesystem/perm options"
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This type represents available options that control the behavior of the function {{lc|std::filesystem::permissions()}}. | This type represents available options that control the behavior of the function {{lc|std::filesystem::permissions()}}. | ||
− | {{ | + | {{satisfies bitmask|perm_options}} |
===Member constants=== | ===Member constants=== |
Revision as of 15:22, 24 August 2022
Defined in header <filesystem>
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enum class perm_options { replace = /* 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). none
represents the empty bitmask; every other enumerator represents a distinct bitmask element.
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
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--
See also
(C++17) |
modifies file access permissions (function) |
(C++17) |
identifies file system permissions (enum) |