std::experimental::filesystem::equivalent
| Defined in header <experimental/filesystem>
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| bool equivalent( const path& p1, const path& p2 ); bool equivalent( const path& p1, const path& p2, error_code& ec ); |
(1) | (filesystem TS) |
Checks whether the paths p1 and p2 refer to the same file or directory and have the same file status as determined by status (symlinks are followed).
If p1 or p2 does not exist or if their file type is not file, directory, or symlink (as determined by is_other), an error is reported.
The non-throwing overload returns false on errors.
Parameters
| p1, p2 | - | paths to check for equivalence |
| ec | - | out-parameter for error reporting in the non-throwing overload |
Return value
true if the p1 and p2 refer to the same file or directory and their file status is the same. false otherwise.
Exceptions
The overload that does not take aerror_code& parameter throws filesystem_error on underlying OS API errors, constructed with p1 as the first argument, p2 as the second 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 Notes
Two paths are considered to resolve to the same file system entity if st_dev and st_ino of their POSIX stat structure, obtained as if by POSIX stat, are equal (meaning, the files are located on the same device at the same location).
In particular, all hard links for the same file or directory are equivalent, and a symlink and its target on the same file system are equivalent.
Example
#include <cstdint> #include <experimental/filesystem> #include <iostream> namespace fs = std::experimental::filesystem; int main() { // hard link equivalency fs::path p1 = "."; fs::path p2 = fs::current_path(); if (fs::equivalent(p1, p2)) std::cout << p1 << " is equivalent to " << p2 << '\n'; // symlink equivalency fs::path p3 = "/lib/libc.so.6"; fs::path p4 = p3.parent_path() / fs::read_symlink(p3); if (fs::equivalent(p3, p4)) std::cout << p3 << " is equivalent to " << p4 << '\n'; }
Possible output:
"." is equivalent to "/var/tmp/test" "/lib/libc.so.6" is equivalent to "/lib/libc-2.12.so"
See also
| determines file attributes determines file attributes, checking the symlink target (function) |