Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help 
std::experi...::copy_file(3)  C++ Standard Libary std::experi...::copy_file(3)

NAME
       std::experimental::filesystem::copy_file	 - std::experimental::filesys-
       tem::copy_file

Synopsis
	  Defined in header <experimental/filesystem>
	  bool copy_file( const	path& from, const path&	to );
	  bool copy_file( const	path& from, const path&	to, error_code&	ec (1)
       (filesystem TS)
	  );
	  bool copy_file( const	path& from, const path&	to, copy_options
	  options );							   (2)
       (filesystem TS)
	  bool copy_file( const	path& from, const path&	to, copy_options
	  options, error_code& ec );

	  1) The default, equivalent to	(2) with  copy_options::none  used  as
       options
	  2)  Copies a single file from	from to	to, using the copy options in-
       dicated by
	  options. The behavior	is undefined if	there is more than one	option
       in any of the
	  copy_options option group present in options (even in	the groups not
       relevant	to
	  copy_file)

	    * If the destination file does not exist,

		     *	copies	the contents and the attributes	of the file to
       which from
		       resolves	to the file to which to	resolves (symlinks are
       followed)

	    * Otherwise, if the	destination file already exists...

		     * If to and from are the same as  determined  by  equiva-
       lent(from, to),
		       report an error
		     * Otherwise, if none of the copy_file control options are
       set in options,
		       report an error
		     * Otherwise, if copy_options::skip_existing is set	in op-
       tions, do nothing
		     *	Otherwise,  if copy_options::overwrite_existing	is set
       in options, copy
		       the contents and	the attributes of the  file  to	 which
       from resolves to
		       the file	to which to resolves
		     *	Otherwise,  if copy_options::update_existing is	set in
       options,	only
		       copy the	file if	from is	newer than to, as  defined  by
       last_write_time()

	  The non-throwing overloads return false if an	error occurs.

Parameters
	  from - path to the source file
	  to   - path to the target file
	  ec	-  out-parameter for error reporting in	the non-throwing over-
       load

Return value
	  true if the file was copied, false otherwise.

Exceptions
	  The overload that does  not  take  a	error_code&  parameter	throws
       filesystem_error	on
	  underlying  OS  API errors, constructed with from as the first argu-
       ment, to	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 er-
       ror_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
	  The  functions  involve  at most one direct or indirect call to sta-
       tus(to) (used both
	  to determine if the file exists, and,	 for  copy_options::update_ex-
       isting option, its
	  last write time)

	  Error	 is  reported  when copy_file is used to copy a	directory: use
       copy for	that.

	  copy_file follows symlinks: use copy_symlink or copy with
	  copy_options::copy_symlinks for that.

Examples
       // Run this code

	#include <fstream>
	#include <iostream>
	#include <experimental/filesystem>
	namespace fs = std::experimental::filesystem;

	int main()
	{
	    fs::create_directory("sandbox");
	    std::ofstream("sandbox/file1.txt").put('a');

	    fs::copy_file("sandbox/file1.txt", "sandbox/file2.txt");

	    // now there are two files in sandbox:
	    std::cout << "file1.txt holds : "
		      << std::ifstream("sandbox/file1.txt").rdbuf() << '\n';
	    std::cout << "file2.txt holds : "
		      << std::ifstream("sandbox/file2.txt").rdbuf() << '\n';

	    // fail to copy directory
	    fs::create_directory("sandbox/abc");
	    try	{
		fs::copy_file("sandbox/abc", "sandbox/def");
	    } catch(fs::filesystem_error& e) {
		std::cout << "Could not	copy sandbox/abc:  "  <<  e.what()  <<
       '\n';
	    }
	    fs::remove_all("sandbox");
	}

Possible output:
	file1.txt holds	: a
	file2.txt holds	: a
	Could  not copy	sandbox/abc: copy_file:	Is a directory:	"sandbox/abc",
       "sandbox/def"

See also
	  copy_options specifies semantics of copy operations
		       (enum)
	  copy_symlink copies a	symbolic link
		       (function)
	  copy	       copies files or directories
		       (function)

http://cppreference.com		  2022.07.31	  std::experi...::copy_file(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::experimental::filesystem::copy_file&sektion=3&manpath=FreeBSD+Ports+15.0>

home | help