std::filesystem::directory_entry::status, std::filesystem::directory_entry::symlink_status
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< cpp | filesystem | directory entry
std::filesystem::file_status status() const; std::filesystem::file_status status( std::error_code& ec ) const; |
(1) | (since C++17) |
std::filesystem::file_status symlink_status() const; std::filesystem::file_status symlink_status( std::error_code& ec ) const; |
(2) | (since C++17) |
1) Returns status of the entry, as if determined by a status call (symlinks are followed to their targets)
2) Returns status of the entry, as if determined by a symlink_status call (symlinks are not followed)
Parameters
ec | - | out-parameter for error reporting in the non-throwing overload |
Return value
The status of the file referred to by the entry.
Exceptions
The overload that does not take a std::error_code& parameter throws filesystem_error on underlying OS API errors, constructed withp
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
Notes
The file status information is usually provided as a byproduct of directory iteration. Both boost.filesystem and the Technical Specification versions of the filesystem library cached the status and these member functions accessed the cached values without the cost of an additional system call, simplifying use of accessors such as is_directory
during directory iteration. Status caching was removed during the merge to C++17 via LWG 2653.
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) |
represents file type and permissions (class) |
(C++17)(C++17) |
determines file attributes determines file attributes, checking the symlink target (function) |
(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 directory (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) |