std::filesystem::directory_entry::exists

bool exists() const;
 (1) (since C++17) 
bool exists( std::error_code& ec ) const noexcept;
 (2) (since C++17)

Checks whether the pointed-to object exists. Effectively returns:

1) std::filesystem::exists(status()),
2) std::filesystem::exists(status(ec)).

Note that status() follows symlinks to their targets.

Parameters

ec - out-parameter for error reporting in the non-throwing overload

Return value

true if the referred-to filesystem object exists.

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.

Example

#include <filesystem>
#include <iostream>
 
int main()
{
    for (auto const str:
    {
        "/usr/bin/cat",
        "/usr/bin/mouse",
        "/usr/bin/python",
        "/usr/bin/bison",
        "/usr/bin/yacc",
        "/usr/bin/c++",
    })
    {
        std::filesystem::directory_entry entry{str};
 
        std::cout << "directory entry " << entry
                  << (entry.exists() ? " exists\n" : " does not exist\n");
    }
}

Possible output:

// Output on a POSIX system:
directory entry "/usr/bin/cat" exist
directory entry "/usr/bin/mouse" does not exist
directory entry "/usr/bin/python" exists
directory entry "/usr/bin/bison" exists
directory entry "/usr/bin/yacc" does not exist
directory entry "/usr/bin/c++" exists

See also

(C++17)
 checks whether path refers to existing file system object
(function)

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