std::experimental::filesystem::absolute,std::experimental::filesystem::system_complete

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Experimental

Technical Specification
Filesystem library(filesystem TS)
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Filesystem library

Classes

filesystem::path
filesystem::filesystem_error
filesystem::directory_entry
filesystem::directory_iterator
filesystem::recursive_directory_iterator
filesystem::file_status

filesystem::space_info
filesystem::file_type
filesystem::perms
filesystem::copy_options
filesystem::directory_options
filesystem::file_time_type

Functions

filesystem::absolute filesystem::system_complete
filesystem::canonical
filesystem::copy
filesystem::copy_file
filesystem::copy_symlink
filesystem::create_directory filesystem::create_directories
filesystem::create_hard_link
filesystem::create_symlink filesystem::create_directory_symlink
filesystem::current_path
filesystem::exists
filesystem::equivalent

filesystem::file_size
filesystem::hard_link_count
filesystem::last_write_time
filesystem::permissions
filesystem::read_symlink
filesystem::remove filesystem::remove_all
filesystem::rename
filesystem::resize_file
filesystem::space
filesystem::status filesystem::symlink_status
filesystem::temp_directory_path

File types

filesystem::is_block_file
filesystem::is_character_file
filesystem::is_directory
filesystem::is_empty
filesystem::status_known

filesystem::is_fifo
filesystem::is_other
filesystem::is_regular_file
filesystem::is_socket
filesystem::is_symlink

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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 ofp relative tobase according to the following rules:

Ifp has both root name and root directory (e.g."C:\users", then the path is returned, unmodified.
Ifp has a root name not followed by a root directory (e.g."C:text.txt"), thenbase is inserted betweenp's root name and the remainder ofp. Formally,p.root_name()/ fs::absolute(base).root_directory()/ fs::absolute(base).relative_path()/ p.relative_path() is returned,
Ifp has no root name, but has a root directory (e.g."/var/tmp/file.txt" on a POSIX system or"\users\ABC\Document.doc" on Windows, then the root name ofbase, if it has one, is prepended top (on a POSIX system,p is not modified, on a Windows system,"\users\ABC\Document.doc" becomes"C:\users\ABC\Document.doc". Formally,fs::absolute(base).root_name()/ p is returned.
Ifp has no root name and no root directory (e.g."../file.txt", then the entirebase is prepended top. 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 pathnamep. On POSIX systems, this is equivalent to(1) with the defaultbase (fs::current_path()). On Windows systems, each logical drive has its own current working directory, and so ifp 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.

[edit]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

[edit]Return value

Returns an absolute (although not necessarily canonical) path formed by combiningp andbase as described above.

[edit]Exceptions

The overload that does not take anerror_code& parameter throwsfilesystem_error on underlying OS API errors, constructed withp 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 anerror_code& parameter sets it to the OS API error code if an OS API call fails, and executesec.clear() if no errors occur. This overload has

noexcept specification:

noexcept

[edit]Notes

On systems that support root names (e.g. Windows), the result of callingabsolute on a relative path that has a root name (e.g."D:file.txt" when the root name ofbase is different will usually result in a non-existent path.

[edit]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"