std::filesystem::file_size
Defined in header <filesystem>
|
||
std::uintmax_t file_size( const std::filesystem::path& p ); std::uintmax_t file_size( const std::filesystem::path& p, |
(1) | (since C++17) |
If p
does not exist, reports an error.
For a regular file p
, returns the size determined as if by reading the st_size
member of the structure obtained by POSIX stat (symlinks are followed)
The result of attempting to determine the size of a directory (as well as any other file that is not a regular file or a symlink) is implementation-defined.
The non-throwing overload returns returns -1 on errors.
Parameters
p | - | path to examine |
ec | - | out-parameter for error reporting in the non-throwing overload |
Return value
The size of the file, in bytes.
Exceptions
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 path argument and the OS error code as the error code argument. 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. Any overload not marked noexcept
may throw std::bad_alloc if memory allocation fails.
Example
#include <iostream> #include <fstream> #include <filesystem> namespace fs = std::filesystem; int main() { fs::path p = fs::current_path() / "example.bin"; std::ofstream(p).put('a'); // create file of size 1 std::cout << "File size = " << fs::file_size(p) << '\n'; fs::remove(p); try { fs::file_size("/dev"); // attempt to get size of a directory } catch(fs::filesystem_error& e) { std::cout << e.what() << '\n'; } }
Possible output:
File size = 1 filesystem error: cannot get file size: Is a directory [/dev]
See also
(C++17) |
changes the size of a regular file by truncation or zero-fill (function) |
(C++17) |
determines available free space on the file system (function) |
returns the size of the file to which the directory entry refers (public member function of std::filesystem::directory_entry ) |