std::filesystem::directory_entry::assign
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< cpp | filesystem | directory entry
C++
Feature test macros (C++20)
Concepts library (C++20)
Metaprogramming library (C++11)
Ranges library (C++20)
Filesystem library (C++17)
Concurrency support library (C++11)
Execution control library (C++26)
std::filesystem::directory_entry
Member functions
Modifiers
directory_entry::assign
Observers
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Non-member functions
void assign( const std::filesystem::path & p );
(1)
(since C++17)
void assign( const std::filesystem::path & p, std::error_code & ec );
(2)
(since C++17)
Assigns new content to the directory entry object. Sets the path to p and calls refresh to update the cached attributes. If an error occurs, the values of the cached attributes are unspecified.
This function does not commit any changes to the filesystem.
[edit] Parameters
p
-
path to the filesystem object to which the directory entry will refer
ec
-
out-parameter for error reporting in the non-throwing overload
[edit] Return value
(none)
[edit] Exceptions
Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.
1) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.
2) Sets a std::error_code & parameter to the OS API error code if an OS API call fails, and executes ec.clear () if no errors occur.
[edit] Example
Run this code
#include <filesystem> #include <fstream> #include <iostream> void print_entry_info(const std::filesystem::directory_entry & entry) { if (std::cout << "The entry " << entry; not entry.exists()) { std::cout << " does not exists on the file system\n"; return; } std::cout << " is "; if (entry.is_directory()) std::cout << "a directory\n"; if (entry.is_regular_file()) std::cout << "a regular file\n"; /*...*/ } int main() { std::filesystem::current_path (std::filesystem::temp_directory_path ()); std::filesystem::directory_entry entry{std::filesystem::current_path ()}; print_entry_info(entry); std::filesystem::path name{"cppreference.html"}; std::ofstream {name} << "C++"; std::cout << "entry.assign();\n"; entry.assign(entry/name); print_entry_info(entry); std::cout << "remove(entry);\n"; std::filesystem::remove (entry); print_entry_info(entry); // the entry still contains old "state" std::cout << "entry.assign();\n"; entry.assign(entry); // or just call entry.refresh() print_entry_info(entry); }
Possible output:
The entry "/tmp" is a directory entry.assign(); The entry "/tmp/cppreference.html" is a regular file remove(entry); The entry "/tmp/cppreference.html" is a regular file entry.assign(); The entry "/tmp/cppreference.html" does not exists on the file system