boost::filesystem::native
I did a Google search to see how to check if a given path is valid, preferably using boost. It brought me here: http://stackoverflow.com/questions/10426671/how-to-check-if-path-is-valid-in... Great! I say to myself. I then Google up the boost doc here: http://www.boost.org/doc/libs/1_62_0/libs/filesystem/doc/portability_guide.h... I then write myself a test: #include <iostream> #include <sstream> #include <boost/filesystem.hpp> int main() { const std::string test1 = "D:\\Programing Projects\\Git Workspace\\Common\\x64\\Debug"; const std::string test2 = "D:\Programing Projects\\Git Workspace\\Common\\x64\\Debug\\"; const std::string test3 = "D:/Programing Projects/Git Workspace/Common/x64/Debug"; const std::string test4 = "D:/Programing Projects/Git Workspace/Common/x64/Debug/"; if (!boost::filesystem::native(test1)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test1 << std::endl; } if (!boost::filesystem::native(test2)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test2 << std::endl; } if (!boost::filesystem::native(test3)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test3 << std::endl; } if (!boost::filesystem::native(test4)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test4 << std::endl; } return 0; } The Test's Output: Boost says the following path is not valid for the native operating system: D:\Programing Projects\Git Workspace\Common\x64\Debug Boost says the following path is not valid for the native operating system: D:Programing Projects\Git Workspace\Common\x64\Debug\ Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug/ What is wrong with that path that it says it is not valid for my native Windows 10 operating system?
can you try it: std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("C:\PATH") << std::endl; std::cout << boost::filesystem::native("\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl; RegardsFernando Gomes. 2016-11-10 18:05 GMT-02:00 Christopher J. Pisz <cpisz@austin.rr.com>:
I did a Google search to see how to check if a given path is valid, preferably using boost.
It brought me here:
http://stackoverflow.com/questions/10426671/how-to-check-if- path-is-valid-in-boostfilesystem
Great! I say to myself. I then Google up the boost doc here: http://www.boost.org/doc/libs/1_62_0/libs/filesystem/doc/por tability_guide.htm
I then write myself a test:
#include <iostream> #include <sstream>
#include <boost/filesystem.hpp>
int main() { const std::string test1 = "D:\\Programing Projects\\Git Workspace\\Common\\x64\\Debug"; const std::string test2 = "D:\Programing Projects\\Git Workspace\\Common\\x64\\Debug\\"; const std::string test3 = "D:/Programing Projects/Git Workspace/Common/x64/Debug"; const std::string test4 = "D:/Programing Projects/Git Workspace/Common/x64/Debug/";
if (!boost::filesystem::native(test1)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test1 << std::endl; }
if (!boost::filesystem::native(test2)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test2 << std::endl; }
if (!boost::filesystem::native(test3)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test3 << std::endl; }
if (!boost::filesystem::native(test4)) { std::cout << "Boost says the following path is not valid for the native operating system: " << test4 << std::endl;
}
return 0; }
The Test's Output:
Boost says the following path is not valid for the native operating system: D:\Programing Projects\Git Workspace\Common\x64\Debug Boost says the following path is not valid for the native operating system: D:Programing Projects\Git Workspace\Common\x64\Debug\ Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug/
What is wrong with that path that it says it is not valid for my native Windows 10 operating system?
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
On 11/10/2016 2:19 PM, Fernando Gomes da Silva wrote:
std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("C:\PATH") << std::endl; std::cout << boost::filesystem::native("\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl;
0 0 0 0 1 0 0 0 Not at all the expected results.
On 11/11/2016 10:40, Christopher J. Pisz wrote:
On 11/10/2016 2:19 PM, Fernando Gomes da Silva wrote:
std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("C:\PATH") << std::endl; std::cout << boost::filesystem::native("\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl;
0 0 0 0 1 0 0 0
Not at all the expected results.
That's especially weird considering that "\P" should be an invalid escape sequence, which should give you a compiler warning/error and/or should make "\PATH" give identical results to "\\PATH". Unless you further escaped these before compiling it?
i did another test here, like this: std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("C:\PATH") << std::endl; std::cout << boost::filesystem::native("\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl; *std::cout << boost::filesystem::native("c\PATH") << std::endl;std::cout << boost::filesystem::native("c\\PATH") << std::endl;std::cout << boost::filesystem::native("c/PATH") << std::endl;std::cout << boost::filesystem::native("c//PATH") << std::endl;* No, in VS2015 - 32bits. Build Success. 2016-11-10 20:19 GMT-02:00 Gavin Lambert <gavinl@compacsort.com>:
On 11/11/2016 10:40, Christopher J. Pisz wrote:
On 11/10/2016 2:19 PM, Fernando Gomes da Silva wrote:
std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("C:\PATH") << std::endl; std::cout << boost::filesystem::native("\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl;
0 0 0 0 1 0 0 0
Not at all the expected results.
That's especially weird considering that "\P" should be an invalid escape sequence, which should give you a compiler warning/error and/or should make "\PATH" give identical results to "\\PATH".
Unless you further escaped these before compiling it?
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
On 11/10/2016 4:25 PM, Fernando Gomes da Silva wrote: SNIP
That's especially weird considering that "\P" should be an invalid escape sequence, which should give you a compiler warning/error and/or should make "\PATH" give identical results to "\\PATH".
Unless you further escaped these before compiling it?
That is wierd. It seems to be an error on rebuild. Disregard those results I guess. I don't know how I got it to run. Here is another test I just tried, making this set of boost functions and thier documentation appear even more confusing to me. #include <iostream> #include <sstream> #include <boost/filesystem.hpp> // Just a garbage console application to do some manual testing. int main() { std::cout << boost::filesystem::native("C://PATH") << std::endl; std::cout << boost::filesystem::native("C:/PATH") << std::endl; std::cout << boost::filesystem::native("C:\\PATH") << std::endl; std::cout << boost::filesystem::native("\\PATH") << std::endl; std::cout << boost::filesystem::native("/PATH") << std::endl; std::cout << boost::filesystem::native("//PATH") << std::endl << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"C://PATH")) << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"C:/PATH")) << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"C:\\PATH")) << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"\\PATH")) << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"/PATH")) << std::endl; std::cout << boost::filesystem::native(reinterpret_cast<char *>(L"//PATH")) << std::endl; return 0; } 0 0 0 0 0 0 1 1 1 0 0 0
On 11/11/2016 11:50, Christopher J. Pisz wrote:
That's especially weird considering that "\P" should be an invalid escape sequence, which should give you a compiler warning/error and/or should make "\PATH" give identical results to "\\PATH".
Disregard this and check my other reply. I was confused and incorrect about how invalid escapes are treated.
reinterpret_cast<char *>(L"C://PATH"))
Never ever do that. Just, no.
On 11/11/2016 09:05, Christopher J. Pisz wrote:
Great! I say to myself. I then Google up the boost doc here: http://www.boost.org/doc/libs/1_62_0/libs/filesystem/doc/portability_guide.h... [...] Boost says the following path is not valid for the native operating system: D:\Programing Projects\Git Workspace\Common\x64\Debug Boost says the following path is not valid for the native operating system: D:Programing Projects\Git Workspace\Common\x64\Debug\ Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug/
What is wrong with that path that it says it is not valid for my native Windows 10 operating system?
After looking at the implementation and reading the docs more carefully: Your assumptions were wrong. :) It turns out that the portability functions (native() and friends) do not check *paths* for validity, they check *path components* (eg. individual filenames). In particular the path separator characters are considered invalid. This is why "\PATH" is considered valid, because this is treated as "PATH", while "\\PATH" is not valid because the backslash is invalid in a filename. So if you wanted to use those, you'd need to wrap it in a path() first and iterate over each element to test if it is valid.
Mere moments ago, quoth I:
So if you wanted to use those, you'd need to wrap it in a path() first and iterate over each element to test if it is valid.
Or, of course, since you're testing a directory name, you can just use exists() to test the path as a whole (since presumably that's what you really care about).
On 11/10/2016 4:51 PM, Gavin Lambert wrote:
On 11/11/2016 09:05, Christopher J. Pisz wrote:
Great! I say to myself. I then Google up the boost doc here: http://www.boost.org/doc/libs/1_62_0/libs/filesystem/doc/portability_guide.h...
[...]
Boost says the following path is not valid for the native operating system: D:\Programing Projects\Git Workspace\Common\x64\Debug Boost says the following path is not valid for the native operating system: D:Programing Projects\Git Workspace\Common\x64\Debug\ Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug Boost says the following path is not valid for the native operating system: D:/Programing Projects/Git Workspace/Common/x64/Debug/
What is wrong with that path that it says it is not valid for my native Windows 10 operating system?
After looking at the implementation and reading the docs more carefully:
Your assumptions were wrong. :)
It turns out that the portability functions (native() and friends) do not check *paths* for validity, they check *path components* (eg. individual filenames).
In particular the path separator characters are considered invalid.
This is why "\PATH" is considered valid, because this is treated as "PATH", while "\\PATH" is not valid because the backslash is invalid in a filename.
So if you wanted to use those, you'd need to wrap it in a path() first and iterate over each element to test if it is valid.
The docs really should clarify that. Google searches all over point to this function for that purpose and it is even marked as an answer on Stack Overflow. If we cannot check for a valid path using this function, then does boost indeed provide us a means for checking that a path is valid? ...Where valid means the given path does not necessarily point to a file or directory, but could point to one if it was first created.
On 11/11/2016 12:07, Christopher J. Pisz wrote:
The docs really should clarify that. Google searches all over point to this function for that purpose and it is even marked as an answer on Stack Overflow.
It is mentioned in the comments on that answer that it only works on the filename portion of the path. And it is mentioned in the docs, as long as you don't interpret "filename" and "path" to be the same thing. In particular note the description of windows_name().
If we cannot check for a valid path using this function, then does boost indeed provide us a means for checking that a path is valid?
...Where valid means the given path does not necessarily point to a file or directory, but could point to one if it was first created.
As I mentioned in my other reply, you can use exists(). Or if it doesn't exist, you can try creating it. Otherwise I'm not aware of anything that'd do it, other than iterating the path and checking each component separately. Most of the time, given a directory path, exists() or create_directories() would be the simplest option (though the latter throws on failure).
On 11/10/2016 5:23 PM, Gavin Lambert wrote:
On 11/11/2016 12:07, Christopher J. Pisz wrote:
The docs really should clarify that. Google searches all over point to this function for that purpose and it is even marked as an answer on Stack Overflow.
It is mentioned in the comments on that answer that it only works on the filename portion of the path.
And it is mentioned in the docs, as long as you don't interpret "filename" and "path" to be the same thing.
In particular note the description of windows_name().
If we cannot check for a valid path using this function, then does boost indeed provide us a means for checking that a path is valid?
...Where valid means the given path does not necessarily point to a file or directory, but could point to one if it was first created.
As I mentioned in my other reply, you can use exists(). Or if it doesn't exist, you can try creating it. Otherwise I'm not aware of anything that'd do it, other than iterating the path and checking each component separately.
Most of the time, given a directory path, exists() or create_directories() would be the simplest option (though the latter throws on failure).
Fair enough! Thank you for solving today's mystery!
participants (5)
-
Christopher J. Pisz -
Fernando Gomes da Silva -
Gavin Lambert