Library: Foundation
Package: Filesystem
Header: Poco/File.h
Description
The File class provides methods for working with a file.
Regarding paths passed to the various methods, note that platform-specific limitations regarding maximum length of the entire path and its components apply.
On Windows, the implementation tries to work around the rather low 260 characters MAX_PATH limit by adding the "\\?\" prefix if a path is absolute and exceeds MAX_PATH characters in length. Note that various limitations regarding usage of the "\\?\" prefix apply in that case, e.g. the path must not contain relative components ("." and "..") and must not use the forward slash ("/") as directory separator.
Inheritance
Direct Base Classes: FileImpl
All Base Classes: FileImpl
Known Derived Classes: TemporaryFile
Member Summary
Member Functions: absolutePath, canExecute, canRead, canWrite, copyDirectory, copyTo, createDirectories, createDirectory, createFile, created, exists, existsAnywhere, freeSpace, getLastModified, getSize, handleLastError, isDevice, isDirectory, isFile, isHidden, isLink, linkTo, list, moveTo, operator !=, operator <, operator <=, operator =, operator ==, operator >, operator >=, path, remove, renameTo, setExecutable, setLastModified, setReadOnly, setSize, setWriteable, swap, totalSpace, usableSpace
Types Aliases
FileSize
using FileSize = FileSizeImpl;
Enumerations
LinkType
Type of link for linkTo().
LINK_HARD = 0
hard link
LINK_SYMBOLIC = 1
symbolic link
Options
OPT_FAIL_ON_OVERWRITE = OPT_FAIL_ON_OVERWRITE_IMPL
Constructors
File
File();
Creates the file.
File
File(
const std::string & path
);
Creates the file.
File
File(
const char * path
);
Creates the file.
File
Creates the file.
File
Copy constructor.
Destructor
~File
~File() override;
Destroys the file.
Member Functions
absolutePath
std::string absolutePath() const;
Returns absolute path. Attempts to find the existing file using curent work directory and the PATH environment variable. If the file doesn't exist, returns empty string.
canExecute
bool canExecute() const;
Returns true if and only if the file is executable.
On Windows, the file must have the extension ".EXE" to be executable. On Unix platforms, the executable permission bit must be set.
canRead
bool canRead() const;
Returns true if and only if the file is readable.
canWrite
bool canWrite() const;
Returns true if and only if the file is writeable.
copyTo
void copyTo(
const std::string & path,
int options = 0
) const;
Copies the file (or directory) to the given path. The target path can be a directory.
A directory is copied recursively. If options is set to OPT_FAIL_ON_OVERWRITE the Method throws an FileExists Exception if the File already exists.
createDirectories
void createDirectories();
Creates a directory (and all parent directories if necessary).
createDirectory
bool createDirectory();
Creates a directory. Returns true if the directory has been created and false if it already exists. Throws an exception if an error occurs.
createFile
bool createFile();
Creates a new, empty file in an atomic operation. Returns true if the file has been created and false if the file already exists. Throws an exception if an error occurs.
created
Timestamp created() const;
Returns the creation date of the file.
Not all platforms or filesystems (e.g. Linux and most Unix platforms with the exception of FreeBSD and Mac OS X) maintain the creation date of a file. On such platforms, created() returns the time of the last inode modification.
exists
bool exists() const;
Returns true if and only if the file exists.
existsAnywhere
bool existsAnywhere() const;
If the file path is relative, searches for the file in the current working directory and the environment paths. If the file path is absolute, the functionality is identical to the exists() call.
freeSpace
FileSize freeSpace() const;
Returns the number of free bytes on the partition containing this path.
getLastModified
Timestamp getLastModified() const;
Returns the modification date of the file.
getSize
FileSize getSize() const;
Returns the size of the file in bytes.
handleLastError 
static void handleLastError(
const std::string & path
);
For internal use only. Throws an appropriate exception for the last file-related error.
isDevice
bool isDevice() const;
Returns true if and only if the file is a device.
isDirectory
bool isDirectory() const;
Returns true if and only if the file is a directory.
isFile
bool isFile() const;
Returns true if and only if the file is a regular file.
isHidden
bool isHidden() const;
Returns true if the file is hidden.
On Windows platforms, the file's hidden attribute is set for this to be true.
On Unix platforms, the file name must begin with a period for this to be true.
isLink
bool isLink() const;
Returns true if and only if the file is a symbolic link.
linkTo
void linkTo(
const std::string & path,
LinkType type = LINK_SYMBOLIC
) const;
Creates a link (symbolic or hard, depending on type argument) at the given path to the file or directory.
May not be supported on all platforms. Furthermore, some operating systems do not allow creating hard links to directories.
list
void list(
std::vector < std::string > & files
) const;
Fills the vector with the names of all files in the directory.
list
void list(
std::vector < File > & files
) const;
Fills the vector with the names of all files in the directory.
moveTo
void moveTo(
const std::string & path,
int options = 0
);
Copies the file (or directory) to the given path and removes the original file. The target path can be a directory. If options is set to OPT_FAIL_ON_OVERWRITE the Method throws an FileExists Exception if the File already exists.
operator != 
bool operator != (
const File & file
) const;
operator <
bool operator < (
const File & file
) const;
operator <=
bool operator <= (
const File & file
) const;
operator =
File & operator = (
const File & file
);
Assignment operator.
operator =
File & operator = (
const std::string & path
);
Assignment operator.
operator =
File & operator = (
const char * path
);
Assignment operator.
operator =
File & operator = (
const Path & path
);
Assignment operator.
operator ==
bool operator == (
const File & file
) const;
operator >
bool operator > (
const File & file
) const;
operator >=
bool operator >= (
const File & file
) const;
path
const std::string & path() const;
Returns the path.
remove
void remove(
bool recursive = false
);
Deletes the file. If recursive is true and the file is a directory, recursively deletes all files in the directory.
renameTo
void renameTo(
const std::string & path,
int options = 0
);
Renames the file to the new name. If options is set to OPT_FAIL_ON_OVERWRITE the Method throws an FileExists Exception if the File already exists.
setExecutable
File & setExecutable(
bool flag = true
);
Makes the file executable (if flag is true), or non-executable (if flag is false) by setting the file's permission bits accordingly.
Does nothing on Windows.
setLastModified
File & setLastModified(
const Timestamp & ts
);
Sets the modification date of the file.
setReadOnly
File & setReadOnly(
bool flag = true
);
Makes the file non-writeable (if flag is true), or writeable (if flag is false) by setting the file's flags in the filesystem accordingly.
setSize
File & setSize(
FileSize size
);
Sets the size of the file in bytes. Can be used to truncate a file.
setWriteable
File & setWriteable(
bool flag = true
);
Makes the file writeable (if flag is true), or non-writeable (if flag is false) by setting the file's flags in the filesystem accordingly.
swap
void swap(
File & file
) noexcept;
Swaps the file with another one.
totalSpace
FileSize totalSpace() const;
Returns the total size in bytes of the partition containing this path.
usableSpace
FileSize usableSpace() const;
Returns the number of usable free bytes on the partition containing this path.
copyDirectory 
void copyDirectory(
const std::string & path,
int options = 0
) const;
Copies a directory. Used internally by copyTo().