Defined in header <filesystem> | ||
|---|---|---|
bool is_empty( const std::filesystem::path& p ); bool is_empty( const std::filesystem::path& p, std::error_code& ec ); | (since C++17) |
Checks whether the given path refers to an empty file or directory.
| p | - | path to examine |
| ec | - | error code to modify in case of error |
true if the file indicated by p or if the type indicated s refers to an empty file or directory, false otherwise. The non-throwing overload returns false if an error occurs.
The overload that does not take a std::error_code& parameter throws 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.
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 3013 | C++17 | error_code overload marked noexcept but can allocate memory | noexcept removed |
|
(C++17)(C++17) | determines file attributes determines file attributes, checking the symlink target (function) |
|
(C++17) | checks whether path refers to existing file system object (function) |
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