std::filesystem::space
From cppreference.com
< cpp | filesystem
Defined in header <filesystem>
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std::filesystem::space_info space( const std::filesystem::path& p ); |
(1) | (since C++17) |
std::filesystem::space_info space( const std::filesystem::path& p, std::error_code& ec ) noexcept; |
(2) | (since C++17) |
Determines the information about the filesystem on which the pathname p is located, as if by POSIX statvfs
.
Populates and returns an object of type filesystem::space_info
, set from the members of the POSIX struct statvfs
as follows:
-
space_info.capacity
is set as if by f_blocks * f_frsize. -
space_info.free
is set to f_bfree * f_frsize. -
space_info.available
is set to f_bavail * f_frsize. - Any member that could not be determined is set to static_cast<std::uintmax_t>(-1).
The non-throwing overload sets all members to static_cast<std::uintmax_t>(-1) on error.
Contents |
[edit] Parameters
p | - | path to examine |
ec | - | out-parameter for error reporting in the non-throwing overload |
[edit] Return value
The filesystem information (a filesystem::space_info
object).
[edit] Exceptions
Any overload not marked noexcept
may throw std::bad_alloc if memory allocation fails.
1) Throws std::filesystem::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.
2) 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.
[edit] Notes
space_info.available
may be less than space_info.free
.
[edit] Example
Run this code
#include <cstdint> #include <filesystem> #include <iostream> void print_space_info(auto const& dirs, int width = 15) { (std::cout << std::left).imbue(std::locale("en_US.UTF-8")); for (const auto s : {"Capacity", "Free", "Available", "Dir"}) std::cout << "│ " << std::setw(width) << s << ' '; for (std::cout << '\n'; auto const& dir : dirs) { std::error_code ec; const std::filesystem::space_info si = std::filesystem::space(dir, ec); for (auto x : {si.capacity, si.free, si.available}) std::cout << "│ " << std::setw(width) << static_cast<std::intmax_t>(x) << ' '; std::cout << "│ " << dir << '\n'; } } int main() { const auto dirs = {"/dev/null", "/tmp", "/home", "/proc", "/null"}; print_space_info(dirs); }
Possible output:
│ Capacity │ Free │ Available │ Dir │ 84,417,331,200 │ 24,069,705,728 │ 21,492,748,288 │ /dev/null │ 84,417,331,200 │ 24,069,705,728 │ 21,492,748,288 │ /tmp │ 250,321,567,744 │ 37,623,181,312 │ 25,152,159,744 │ /home │ 0 │ 0 │ 0 │ /proc │ -1 │ -1 │ -1 │ /null
[edit] See also
(C++17) |
information about free and available space on the filesystem (class) |