std::experimental::filesystem:: absolute, std::experimental::filesystem:: system_complete
From cppreference.com
<
cpp
|
experimental
|
fs
|
Defined in header
<experimental/filesystem>
|
||
|
path absolute
(
const
path
&
p,
const
path
&
base
=
current_path
(
)
)
;
|
(1) | (filesystem TS) |
|
path system_complete
(
const
path
&
p
)
;
path system_complete ( const path & p, error_code & ec ) ; |
(2) | (filesystem TS) |
1)
Returns absolute path of
p
relative to
base
according to the following rules:
-
- If p has both root name and root directory (e.g. "C:\users" , then the path is returned, unmodified.
- If p has a root name not followed by a root directory (e.g. "C:text.txt" ), then base is inserted between p 's root name and the remainder of p . Formally, p. root_name ( ) / fs :: absolute ( base ) . root_directory ( ) / fs :: absolute ( base ) . relative_path ( ) / p. relative_path ( ) is returned,
- If p has no root name, but has a root directory (e.g. "/var/tmp/file.txt" on a POSIX system or "\users \A BC\Document.doc" on Windows, then the root name of base , if it has one, is prepended to p (on a POSIX system, p is not modified, on a Windows system, "\users \A BC\Document.doc" becomes "C:\users \A BC\Document.doc" . Formally, fs :: absolute ( base ) . root_name ( ) / p is returned.
- If p has no root name and no root directory (e.g. "../file.txt" , then the entire base is prepended to p . Formally, absolute ( base ) / p is returned.
2)
Obtains the absolute path that identifies the file that the OS file opening API would access given the pathname
p
. On POSIX systems, this is equivalent to
(1)
with the default
base
(
fs::current_path()
). On Windows systems, each logical drive has its own current working directory, and so if
p
is not already absolute and has a root name component (e.g.
"E:filename.txt"
, that drive's current working directory is used, which may have been set by an earlier executed program.
Parameters
| p | - | path to convert to absolute form |
| base | - | path (not necessarily absolute) to serve as the starting location |
| ec | - | out-parameter for error reporting in the non-throwing overload |
Return value
Returns an absolute (although not necessarily canonical) path formed by combining p and base as described above.
Exceptions
The overload that does not take an error_code & parameter throws filesystem_error on underlying OS API errors, constructed with p as the first argument, base 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 an 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
noexcept
specification:
noexcept
Notes
On systems that support root names (e.g. Windows), the result of calling
absolute
on a relative path that has a root name (e.g.
"D:file.txt"
when the root name of
base
is different will usually result in a non-existent path.
Example
Run this code
#include <filesystem> #include <iostream> namespace fs = std::experimental::filesystem; int main() { fs::path p = "C:cl.exe"; std::cout << "Current path is " << fs::current_path() << '\n' << "Absolute path for " << p << " is " << fs::absolute(p) << '\n' << "System complete path for " << p << " is " << fs::system_complete(p) << '\n'; }
Possible output:
Current path is "D:/local/ConsoleApplication1" Absolute path for "C:cl.exe" is "C:/local/ConsoleApplication1/cl.exe" System complete path for "C:cl.exe" is "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\cl.exe"
See also
|
composes a canonical path
(function) |