Difference between revisions of "cpp/filesystem/absolute"

Revision as of 22:23, 29 May 2021

Returns a path referencing the same file system location as p, for which filesystem::is_absolute() is true. The non-throwing overload returns default-constructed path if an error occurs.

Parameters

Return value

Returns an absolute (although not necessarily canonical) pathname referencing the same file as p.

Exceptions

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.
The overload that does not take a std::error_code& parameter 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. 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.

Notes

Implementations are encouraged to not consider p not existing to be an error.

For POSIX-based operating systems, std::filesystem::absolute(p) is equivalent to std::filesystem::current_path() / p except for when p is the empty path.

For Windows, std::filesystem::absolute may be implemented as a call to GetFullPathNameW.

Example

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
    std::filesystem::path p = "foo.c";
    std::cout << "Current path is " << fs::current_path() << '\n';
    std::cout << "Absolute path for " << p << " is " 
              << std::filesystem::absolute(p) << '\n';
}

Current path is "/tmp/1622355667.5363104"
Absolute path for "foo.c" is "/tmp/1622355667.5363104/foo.c"

See also