void assign( const std::filesystem::path& p ); void assign( const std::filesystem::path& p, std::error_code& ec ); | (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.
| p | - | path to the filesystem object to which the directory entry will refer |
| ec | - | out-parameter for error reporting in the non-throwing overload |
(none).
The overload that does not take a std::error_code& parameter throws 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. The overload taking a std::error_code& parameter sets it to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur. Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.
#include <filesystem>
#include <fstream>
#include <iostream>
void print_entry_info(const std::filesystem::directory_entry& entry)
{
std::cout << "the entry " << entry;
if (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
| assigns contents (public member function) |
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https://en.cppreference.com/w/cpp/filesystem/directory_entry/assign