std::experimental::filesystem::file_size
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< cpp | experimental | fs
| Defined in header <experimental/filesystem>
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| std::uintmax_t file_size( const path& p ); std::uintmax_t file_size( const path& p, error_code& ec ); |
(1) | (filesystem TS) |
Returns the size of the regular file p, determined as if by reading the st_size member of the structure obtained by POSIX stat (symlinks are followed)
Attempting to determine the size of a directory (as well as any other file that is not a regular file or a symlink) is treated as an error.
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 aerror_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 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 <experimental/filesystem> namespace fs = std::experimental::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
| changes the size of a regular file by truncation or zero-fill (function) | |
| determines available free space on the file system (function) |