std::filesystem::is_regular_file

Defined in header `<filesystem>`
bool is_regular_file( std::filesystem::file_status s ) noexcept;	(1)	(since C++17)
bool is_regular_file( const std::filesystem::path& p );	(2)	(since C++17)
bool is_regular_file( const std::filesystem::path& p, std::error_code& ec ) noexcept;	(3)	(since C++17)

Checks if the given file status or path corresponds to a regular file.

1) Equivalent to s.type() == file_type::regular.

2,3) Equivalent to is_regular_file(status(p)) or is_regular_file(status(p, ec)) respectively.

Parameters

s	-	file status to check
p	-	path to examine
ec	-	error code to store the error status to

Return value

true if the file indicated by p or if the type indicated by s refers to a regular file, false otherwise. The non-throwing overload returns false if an error occurs.

Exceptions

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.

2,3) 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.

Notes

The throwing overload is additionally specified to throw std::filesystem::filesystem_error if status(p) would throw.

Example

Run this code

#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 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 (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

file_type (C++17)	the type of a file (enum)
statussymlink_status (C++17)(C++17)	determines file attributes determines file attributes, checking the symlink target (function)
file_status (C++17)	represents file type and permissions (class)
status_known (C++17)	checks whether file status is known (function)
is_block_file (C++17)	checks whether the given path refers to block device (function)
is_character_file (C++17)	checks whether the given path refers to a character device (function)
is_directory (C++17)	checks whether the given path refers to a directory (function)
is_fifo (C++17)	checks whether the given path refers to a named pipe (function)
is_other (C++17)	checks whether the argument refers to an other file (function)
is_socket (C++17)	checks whether the argument refers to a named IPC socket (function)
is_symlink (C++17)	checks whether the argument refers to a symbolic link (function)
exists (C++17)	checks whether path refers to existing file system object (function)
is_regular_file	checks whether the directory entry refers to a regular file (public member function of `std::filesystem::directory_entry`)

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