# std::filesystem::exists

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< cpp‎ | filesystem

Defined in header `<filesystem>` |  |
bool exists( std::filesystem::file_status s ) noexcept; | (1) | (since C++17)
bool exists( const std::filesystem::path & p ); bool exists( const std::filesystem::path & p, std::error_code & ec ) noexcept; | (2) | (since C++17)

Checks if the given file status or path corresponds to an existing file or directory.

1) Equivalent to status_known(s) && s.type() != file_type::not_found.
2) Let `s` be a std::filesystem::file_status determined as if by status(p) or status(p, ec) (symlinks are followed), respectively. Returns exists(s). The non-throwing overload calls ec.clear() if status_known(s).

### Parameters

s | - | file status to check
p | - | path to examine
ec | - | out-parameter for error reporting in the non-throwing overload

### Return value

true if the given path or file status corresponds to an existing file or directory, false otherwise.

### Exceptions

2) 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.

### Notes

The information provided by this function is usually also provided as a byproduct of directory iteration. During directory iteration, calling `exists(*iterator)` is less efficient than `exists(iterator->status())`

### Example

| This section is incomplete Reason: switch to directory_entry::exists

Run this code

    #include <iostream>
    #include <fstream>
    #include <cstdint>
    #include <filesystem>
    namespace fs = std::filesystem;

    void demo_exists(const fs::path& p, fs::file_status s = fs::file_status{})
    {
        std::cout << p;
        if(fs::status_known(s) ? fs::exists(s) : fs::exists(p))
            std::cout << " exists\n";
        else
            std::cout << " does not exist\n";
    }
    int main()
    {
        fs::create_directory("sandbox");
        std::ofstream("sandbox/file"); // create regular file
        fs::create_symlink("non-existing", "sandbox/symlink");

        demo_exists("sandbox");
        for(auto it = fs::directory_iterator("sandbox"); it != fs::directory_iterator(); ++it)
            demo_exists(*it, it->status()); // use cached status from directory entry
        fs::remove_all("sandbox");
    }

Output:

    "sandbox" exists
    "sandbox/file" exists
    "sandbox/symlink" does not exist

### See also

statussymlink_status (C++17)(C++17) | determines file attributes determines file attributes, checking the symlink target (function)
file_status (C++17) | represents file type and permissions (class)
exists | checks whether directory entry refers to existing file system object (public member function of `std::filesystem::directory_entry`)

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