| Classes | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Functions | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| File types | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Defined in header <filesystem> | ||
bool is_block_file(std::filesystem::file_status s)noexcept; | (1) | (since C++17) |
bool is_block_file(conststd::filesystem::path& p); | (2) | (since C++17) |
bool is_block_file(conststd::filesystem::path& p,std::error_code& ec)noexcept; | (3) | (since C++17) |
Checks if the given file status or path corresponds to a block special file, as if determined by the POSIXS_ISBLK. Examples of block special files are block devices such as/dev/sda or/dev/loop0 on Linux.
Contents |
| s | - | file status to check |
| p | - | path to examine |
| ec | - | out-parameter for error reporting in the non-throwing overload |
true if the file indicated byp or if the type indicateds refers to a block device. The non-throwing overload returnsfalse if an error occurs.
Any overload not markednoexcept may throwstd::bad_alloc if memory allocation fails.
#include <cstdio>#include <cstring>#include <filesystem>#include <fstream>#include <iostream>#include <sys/socket.h>#include <sys/stat.h>#include <sys/un.h>#include <unistd.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"); fs::create_directory("sandbox/dir");std::ofstream{"sandbox/file"};// create regular file fs::create_symlink("file","sandbox/symlink"); mkfifo("sandbox/pipe",0644); 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,reinterpret_cast<sockaddr*>(&addr), sizeof addr); // demo different status accessorsfor(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 (prefer std::unique_ptr-based custom deleters) 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
(C++17)(C++17) | determines file attributes determines file attributes, checking the symlink target (function)[edit] |
(C++17) | represents file type and permissions (class)[edit] |
(C++17) | checks whether file status is known (function)[edit] |
(C++17) | checks whether the given path refers to a character device (function)[edit] |
(C++17) | checks whether the given path refers to a directory (function)[edit] |
(C++17) | checks whether the given path refers to a named pipe (function)[edit] |
(C++17) | checks whether the argument refers to another file (function)[edit] |
(C++17) | checks whether the argument refers to a regular file (function)[edit] |
(C++17) | checks whether the argument refers to a named IPC socket (function)[edit] |
(C++17) | checks whether the argument refers to a symbolic link (function)[edit] |
(C++17) | checks whether path refers to existing file system object (function)[edit] |
| checks whether the directory entry refers to block device (public member function of std::filesystem::directory_entry)[edit] |
