std::filesystem::directory_entry::exists
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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
Observers
directory_entry::exists
(until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)
Non-member functions
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.
[edit] Parameters
ec
-
out-parameter for error reporting in the non-throwing overload
[edit] Return value
true if the referred-to filesystem object exists.
[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 <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