std::filesystem::is_directory
From cppreference.com
< cpp | filesystem
Defined in header <filesystem>
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bool is_directory( std::filesystem::file_status s ); |
(1) | (since C++17) |
bool is_directory( const std::filesystem::path& p ); bool is_directory( const std::filesystem::path& p, std::error_code& ec ); |
(2) | (since C++17) |
Checks if the given file status or path corresponds to a directory.
1) Equivalent to s.type() == file_type::directory.
2) Equivalent to is_directory(status(p)) or is_directory(status(p, ec)), respectively.
Parameters
s | - | file status to check |
p | - | path to query |
ec | - | error code to modify in case of errors |
Return value
true if the file indicated by p
or if the type indicated s
refers to a directory, false otherwise. The non-throwing overload returns false if an error occurs.
Exceptions
1)
noexcept specification:
noexcept
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 argument and the OS error code as the error code argument. std::bad_alloc may be thrown if memory allocation fails. 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. This overload has noexcept specification:
noexcept
Example
Run this code
#include <iostream> #include <fstream> #include <cstdio> #include <cstring> #include <filesystem> #include <unistd.h> #include <sys/socket.h> #include <sys/un.h> #include <sys/stat.h> namespace fs = std::filesystem; void demo_status(const fs::path& p, fs::file_status s) { std::cout << p; // alternative: switch(s.type()) { case fs::file_type::regular: ...} if(fs::is_regular_file(s)) std::cout << " is a regular file\n"; if(fs::is_directory(s)) std::cout << " is a directory\n"; if(fs::is_block_file(s)) std::cout << " is a block device\n"; if(fs::is_character_file(s)) std::cout << " is a character device\n"; if(fs::is_fifo(s)) std::cout << " is a named IPC pipe\n"; if(fs::is_socket(s)) std::cout << " is a named IPC socket\n"; if(fs::is_symlink(s)) std::cout << " is a symlink\n"; if(!fs::exists(s)) std::cout << " does not exist\n"; } int main() { // create files of different kinds fs::create_directory("sandbox"); std::ofstream("sandbox/file"); // create regular file fs::create_directory("sandbox/dir"); mkfifo("sandbox/pipe", 0644); struct sockaddr_un addr; addr.sun_family = AF_UNIX; std::strcpy(addr.sun_path, "sandbox/sock"); int fd = socket(PF_UNIX, SOCK_STREAM, 0); bind(fd, (struct sockaddr*)&addr, sizeof addr); fs::create_symlink("file", "sandbox/symlink"); // demo different status accessors for(auto it = fs::directory_iterator("sandbox"); it != fs::directory_iterator(); ++it) demo_status(*it, it->symlink_status()); // use cached status from directory entry demo_status("dev/null", fs::status("/dev/null")); // direct calls to status demo_status("dev/sda", fs::status("/dev/sda")); demo_status("sandbox/no", fs::status("/sandbox/no")); // cleanup close(fd); fs::remove_all("sandbox"); }
Possible output:
"sandbox/file" is a regular file "sandbox/dir" is a directory "sandbox/pipe" is a named IPC pipe "sandbox/sock" is a named IPC socket "sandbox/symlink" is a symlink "dev/null" is a character device "dev/sda" is a block device "sandbox/no" does not exist
See also
(C++17)(C++17) |
determines file attributes determines file attributes, checking the symlink target (function) |
(C++17) |
represents file type and permissions (class) |
(C++17) |
checks whether file status is known (function) |
(C++17) |
checks whether the given path refers to block device (function) |
(C++17) |
checks whether the given path refers to a character device (function) |
(C++17) |
checks whether the given path refers to a named pipe (function) |
(C++17) |
checks whether the argument refers to an other file (function) |
(C++17) |
checks whether the argument refers to a regular file (function) |
(C++17) |
checks whether the argument refers to a named IPC socket (function) |
(C++17) |
checks whether the argument refers to a symbolic link (function) |
(C++17) |
checks whether path refers to existing file system object (function) |
status of the file designated by this directory entry symlink_status of the file designated by this directory entry (public member function of std::filesystem::directory_entry ) |