c++ std::filesystem discussion, std::filesystem was added to the ISO C++ standard library in C++17
Specification available from http://en.cppreference.com/w/cpp/filesystem
Questions tagged [std-filesystem]
165 questions
52
votes
2 answers
VS2017: E0135 namespace "std" has no member "filesystem"
In order to use: std::filesystem from the C++17 library, my project was migrated from vs2015 to vs2017.
My project compiles and runs without error, the lib is included without error, but when trying to use std::filesystem I get the following:
It…
LearnMore
- 695
- 1
- 5
- 12
29
votes
2 answers
What is the C++17 equivalent to boost::filesystem::unique_path()?
std::filesystem on C++17, and std::experimental::filesystem for many pre-C++17 compilers, are based on boost::filesystem and almost all of it is obvious to port to the newer std.
But I see no std::filesystem equivalent to…
Larry Gritz
- 13,331
- 5
- 42
- 42
27
votes
4 answers
Link errors using members in C++17
I'm using gcc 7.2 on Ubuntu 16.04, and I need to use the new filesystem library from C++17. Even though there is indeed a library called experimental/filesystem, I can't use any of its members. For example, when I try to compile this file:
#include…
Willie Jeng
- 323
- 1
- 4
- 9
20
votes
3 answers
Native path separator bug in C++17 std::filesystem::path?
I encountered a problem when upgrading from #include to #include . It seems that the std::filesystem::path::wstring method is not returning the same string as in experimental::filesystem. I wrote the following…
Garland
- 911
- 7
- 22
15
votes
1 answer
Why is it not possible to construct a `std::filesystem::path` from `std::filesystem::path` iterators?
The following piece of code aims to strip the first part of a path in case it exists:
#include
std::filesystem::path strip_prefix(std::filesystem::path p)
{
if (auto it{p.begin()}; it != p.end())
{
++it;
return…
Ton van den Heuvel
- 10,157
- 6
- 43
- 82
14
votes
1 answer
How to convert `std::filesystem::file_time_type` to a string using GCC 9
I'm trying to format the modification time of a file as a string (UTC). The following code compiles with GCC 8, but not GCC 9.
#include
#include
#include
#include
#include
namespace fs =…
tttapa
- 1,397
- 12
- 26
13
votes
1 answer
How to get the last directory in a std::filesystem::path?
I have a path to a directory and I want to get the name of that directory, using C++'s std::filesystem. For example, if the path was:
std::filesystem::path fake_path("C:\\fake\\path\\to\\my_directory\\");
I would want to get "my_directory".
I've…
Withad
- 503
- 1
- 6
- 12
13
votes
3 answers
Passing std::filesystem::path to a function segfaults
When I attempt to use std::filesystem::path as a function argument, it segfaults on my machine. Here is a minimal example:
#include
void thing(const std::filesystem::path& p) {
return;
}
int main() {
thing("test");
return…
Astrognome
- 303
- 3
- 9
13
votes
1 answer
How to remove quotation marks from std::filesystem::path
If I use functions like absolute() I always get a path which contains quotation marks.
Is there a way within the filesystem functions to remove this quotation marks which enables it to use with e.g. std::ifstream?
fs::path p2 { "./test/hallo.txt"…
Klaus
- 24,205
- 7
- 58
- 113
12
votes
1 answer
What does std::filesystem::is_regular_file(path) mean on Windows?
About std::filesystem::is_regular_file(path), cppreference.com says:
Checks if the given file status or path corresponds to a regular file […] Equivalent to s.type() == file_type::regular.
For example, in the Linux kernel, file types are declared…
Amit
- 645
- 1
- 3
- 19
11
votes
4 answers
Why does std::filesystem provide so many non-member functions?
Consider for example
file_size. To get the size of a file we will be using
std::filesystem::path p = std::filesystem::current_path();
// ... usual "does this exist && is this a file" boilerplate
auto n = std::filesystem::file_size(p);
Nothing…
dlw
- 323
- 2
- 14
10
votes
3 answers
No operator+ for std::filesystem::path?
It is possible to append multiple paths in a row using the / operator:
std::filesystem::path p1{"A"};
auto p2 = p1 / "B" / "C";
which is rather convenient. However, concat only offers +=:
std::filesystem::path p1{"A"};
auto p2 = p1 / "B" /…
Touloudou
- 2,079
- 1
- 17
- 28
10
votes
2 answers
Get the absolute path from std::filesystem::path c++
I have this piece of code
auto path = std::filesystem::path("/root/home/../opt/.");
I had tried std::filesystem::absolute() but then realized it is for something else than the reasult I want
My question is how can i convert that relative path to…
Dev-il
- 157
- 1
- 8
10
votes
2 answers
Can filesystem::canonical be used to prevent filepath injection for filepaths passed to fstream
I have a public folder pub with subfolders and files in it. A user gives me now a relative filepath, I perform some mappings, and I read the file with fstream and return it to the user.
The problem is now if the user gives me a path like e.g.…
ezegoing
- 526
- 1
- 4
- 18
8
votes
1 answer
How to properly handle windows paths with the long path prefix with std::filesystem::path
std::filesystem::path doesn't seem to be aware of the windows long path magic prefix.
Is this per design or is there a mode/flag/compiler switch/3rd party library which can be used?
f.e.
for a path like C:\temp\test.txt, the root_name is C: and the…
ridilculous
- 624
- 3
- 16