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The QDir class provides access to directory structures and their contents. More...
#include <QDir>
Note: All the functions in this class are reentrant.
The QDir class provides access to directory structures and their contents.
A QDir is used to manipulate path names, access information regarding paths and files, and manipulate the underlying file system.
A QDir can point to a file using either a relative or an absolute path. Absolute paths begin with the directory separator "/" (optionally preceded by a drive specification under Windows). If you always use "/" as a directory separator, Qt will translate your paths to conform to the underlying operating system. Relative file names begin with a directory name or a file name and specify a path relative to the current directory.
An example of an absolute path is the string "/tmp/quartz", a relative path might look like "src/fatlib". You can use the isRelative() or isAbsolute() functions to check if a QDir is using a relative or an absolute file path. Call makeAbsolute() to convert a relative QDir to an absolute one. For a simplified path use cleanPath(). To obtain a path which has no symbolic links or redundant ".." elements use canonicalPath(). The path can be set with setPath(), and changed with cd() and cdUp().
The current() path (and currentPath()), refers to the application's working directory. A QDir's own path is set and retrieved with setPath() and path().
QDir provides several static convenience functions, for example, setCurrent() to set the application's working directory and current() and currentPath() to retrieve the application's working directory. Access to some common paths is provided with the static functions, home(), root(), and temp() which return QDir objects or homePath(), rootPath(), and tempPath() which return the path as a string. For the application's directory, see QApplication::applicationDirPath().
The number of entries in a directory is returned by count(). You can obtain a string list of the names of all the files and directories in a directory with entryList(). If you prefer a list of QFileInfo pointers use entryInfoList(). Both these functions can apply a name filter, an attributes filter (e.g. read-only, files not directories, etc.), and a sort order. The filters and sort may be set with calls to setNameFilters(), setFilter() and setSorting(). They may also be specified in the entryList() and entryInfoList()'s arguments. You can test to see if a filename matches a filter using match().
Create a new directory with mkdir(), rename a directory with rename() and remove an existing directory with rmdir(). Remove a file with remove(). You can query a directory with exists(), isReadable(), isAbsolute(), isRelative(), and isRoot(). You can use refresh() to re-read the directory's data from disk.
To get a path with a filename use filePath(), and to get a directory name use dirName(); neither of these functions checks for the existence of the file or directory. The path() (changeable with setPath()), absolutePath(), absoluteFilePath(), and canonicalPath() are also available.
The list of root directories is provided by drives(); on Unix systems this returns a list containing a single root directory, "/"; on Windows the list will usually contain "C:/", and possibly "D:/", etc.
It is easiest to work with "/" separators in Qt code. If you need to present a path to the user or need a path in a form suitable for a function in the underlying operating system use convertSeparators().
Examples:
See if a directory exists.
QDir dir("example"); // "./example" if (!dir.exists()) qWarning("Cannot find the example directory");
(Alternatively, we could use the static convenience function QFile::exists().)
Traversing directories and reading a file.
QDir dir = QDir::root(); // "/" if (!dir.cd("tmp")) { // "/tmp" qWarning("Cannot find the \"/tmp\" directory"); } else { QFile file(dir.filePath("ex1.txt")); // "/tmp/ex1.txt" if (!file.open(QIODevice::ReadWrite)) qWarning("Cannot create the file %s", file.name()); }
A program that lists all the files in the current directory (excluding symbolic links), sorted by size, smallest first:
#include <stdio.h> #include <qdir.h> int main(int argc, char **argv) { QDir dir; dir.setFilter(QDir::Files | QDir::Hidden | QDir::NoSymLinks); dir.setSorting(QDir::Size | QDir::Reversed); QFileInfoList list = dir.entryInfoList(); printf(" Bytes Filename\n"); for (int i = 0; i < list.size(); ++i) { QFileInfo fi = list.at(i); printf("%10li %s\n", fi.size(), fi.fileName().latin1()); } return 0; }
See also QApplication::applicationDirPath().
This enum describes the filtering options available to QDir; e.g. for entryList() and entryInfoList(). The filter value is specified by combining values from the following list using the OR operator:
QDir::Dirs | List directories that match the filters. |
QDir::AllDirs | List all directories; i.e. don't apply the filters to directory names. |
QDir::Files | List files only. |
QDir::Drives | List disk drives (ignored under Unix). |
QDir::NoSymLinks | Do not list symbolic links (ignored by operating systems that don't support symbolic links). |
QDir::All | List directories, files, drives and symlinks (this does not list broken symlinks unless you specify System). NoSymLinks flags. |
QDir::Readable | List files for which the application has read access. |
QDir::Writable | List files for which the application has write access. |
QDir::Executable | List files for which the application has execute access. Executables needs to be combined with Dirs or Files. |
QDir::Modified | Only list files that have been modified (ignored under Unix). |
QDir::Hidden | List hidden files (on Unix, files starting with a .). |
QDir::System | List system files (on Unix, FIFOs, sockets and device files) |
QDir::CaseSensitive | The filter should be case sensitive if the file system is case sensitive. |
If you do not set any of Readable, Writable, or Executable, QDir will set all three of them. This makes the default easy to write, and at the same time useful.
Examples: Readable|Writable means list all files for which the application has read access, write access or both. Dirs|Drives means list drives, directories, all files that the application can read, write or execute, and also symlinks to such files/directories.
The Filters typedef can store a combination of Filter values.
QDir::Recursive | |
QDir::NonRecursive |
This enum describes the sort options available to QDir, e.g. for entryList() and entryInfoList(). The sort value is specified by OR-ing together values from the following list:
QDir::Name | Sort by name. |
QDir::Time | Sort by time (modification time). |
QDir::Size | Sort by file size. |
QDir::Unsorted | Do not sort. |
QDir::DirsFirst | Put the directories first, then the files. |
QDir::DirsLast | Put the files first, then the directories. |
QDir::Reversed | Reverse the sort order. |
QDir::IgnoreCase | Sort case-insensitively. |
You can only specify one of the first four.
If you specify both DirsFirst and Reversed, directories are still put first, but in reverse order; the files will be listed after the directories, again in reverse order.
The SortFlags typedef can store a combination of SortFlag values.
Constructs a QDir object that is a copy of the QDir object for directory dir.
See also operator=().
Constructs a QDir pointing to the given directory path. If path is empty the program's working directory, ("."), is used.
See also currentPath().
Destroys the QDir object frees up its resources. This has no effect on the underlying directory in the file system.
Returns the absolute path name of a file in the directory. Does not check if the file actually exists in the directory; but see exists(). Redundant multiple separators or "." and ".." directories in fileName are not removed (see cleanPath()).
If acceptAbsPath is true a fileName starting with a separator "/" will be returned without change. If acceptAbsPath is false an absolute path will be prepended to the fileName and the resultant string returned.
See also filePath() and canonicalPath().
Returns the absolute path (a path that starts with "/" or with a drive specification), which may contain symbolic links, but never contains redundant ".", ".." or multiple separators.
See also setPath(), canonicalPath(), exists(), cleanPath(), dirName(), and absoluteFilePath().
Returns the canonical path, i.e. a path without symbolic links or redundant "." or ".." elements.
On systems that do not have symbolic links this function will always return the same string that absolutePath() returns. If the canonical path does not exist (normally due to dangling symbolic links) canonicalPath() returns an empty string.
Example:
QString bin = "/local/bin"; // where /local/bin is a symlink to /usr/bin QDir binDir(bin); QString canonicalBin = binDir.canonicalPath(); // canonicalBin now equals "/usr/bin" QString ls = "/local/bin/ls"; // where ls is the executable "ls" QDir lsDir(ls); QString canonicalLs = lsDir.canonicalPath(); // canonicalLS now equals "/usr/bin/ls".
See also path(), absolutePath(), exists(), cleanPath(), dirName(), absoluteFilePath(), and QString::isNull().
Changes the QDir's directory to dirName.
If acceptAbsPath is true a path starting with separator "/" will cause the function to change to the absolute directory. If acceptAbsPath is false any number of separators at the beginning of dirName will be removed and the function will descend into dirName.
Returns true if the new directory exists and is readable; otherwise returns false. Note that the logical cd() operation is not performed if the new directory does not exist.
Calling cd("..") is equivalent to calling cdUp().
See also cdUp(), isReadable(), exists(), and path().
Changes directory by moving one directory up from the QDir's current directory.
Returns true if the new directory exists and is readable; otherwise returns false. Note that the logical cdUp() operation is not performed if the new directory does not exist.
See also cd(), isReadable(), exists(), and path().
Removes all multiple directory separators "/" and resolves any "."s or ".."s found in the path, path.
Symbolic links are kept. This function does not return the canonical path, but rather the simplest version of the input. For example, "./local" becomes "local", "local/../bin" becomes "bin" and "/local/usr/../bin" becomes "/local/bin".
See also absolutePath() and canonicalPath().
Returns pathName with the '/' separators converted to separators that are appropriate for the underlying operating system.
On Windows, convertSeparators("c:/winnt/system32") returns "c:\winnt\system32".
The returned string may be the same as the argument on some operating systems, for example on Unix.
See also separator().
Returns the total number of directories and files in the directory.
Equivalent to entryList().count().
See also operator[]() and entryList().
Returns the absolute path of the application's current directory. See currentPath() for details.
See also drives(), homePath(), rootPath(), and tempPath().
Returns the absolute path of the application's current directory.
See also current(), drives(), homePath(), rootPath(), and tempPath().
Returns the name of the directory; this is not the same as the path, e.g. a directory with the name "mail", might have the path "/var/spool/mail". If the directory has no name (e.g. it is the root directory) an empty string is returned.
No check is made to ensure that a directory with this name actually exists; but see exists().
See also path(), filePath(), absolutePath(), and absoluteFilePath().
Returns a list of the root directories on this system. On Windows this returns a number of QFileInfo objects containing "C:/", "D:/", etc. On other operating systems, it returns a list containing just one root directory (i.e. "/").
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns true if the file called name exists; otherwise returns false.
If acceptAbsPath is true a path starting with separator "/" will check the file with the absolute path. If acceptAbsPath is false any number of separators at the beginning of name will be removed and the resultant file name will be checked.
See also QFileInfo::exists() and QFile::exists().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns true if the directory exists; otherwise returns false. (If a file with the same name is found this function will return false).
See also QFileInfo::exists() and QFile::exists().
Returns the path name of a file in the directory. Does not check if the file actually exists in the directory; but see exists(). If the QDir is relative the returned path name will also be relative. Redundant multiple separators or "." and ".." directories in fileName are not removed (see cleanPath()).
If acceptAbsPath is true a fileName starting with a separator "/" will be returned without change. If acceptAbsPath is false an absolute path will be prepended to the fileName and the resultant string returned.
See also dirName(), absoluteFilePath(), isRelative(), and canonicalPath().
Returns the value set by setFilter()
Returns the user's home directory. See homePath() for details.
See also drives(), currentPath(), rootPath(), and tempPath().
Returns the user's home directory.
Under Windows the HOME environment variable is used. If this does not exist the USERPROFILE environment variable is used. If that does not exist the path is formed by concatenating the HOMEDRIVE and HOMEPATH environment variables. If they don't exist the rootPath() is used (this uses the SystemDrive environment variable). If none of these exist "C:" is used.
Under non-Windows operating systems the HOME environment variable is used if it exists, otherwise rootPath() is used.
See also home(), drives(), currentPath(), rootPath(), and tempPath().
Returns true if the directory's path is absolute; otherwise returns false. See isAbsolutePath().
See also isRelative(), makeAbsolute(), and cleanPath().
Returns true if path is absolute; returns false if it is relative.
See also isAbsolute(), isRelativePath(), makeAbsolute(), and cleanPath().
Returns true if the directory is readable and we can open files by name; otherwise returns false.
Warning: A false value from this function is not a guarantee that files in the directory are not accessible.
See also QFileInfo::isReadable().
Returns true if the directory path is relative; otherwise returns false. (Under Unix a path is relative if it does not start with a "/").
See also makeAbsolute(), isAbsolute(), isAbsolutePath(), and cleanPath().
Returns true if path is relative; returns false if it is absolute.
See also isRelative(), isAbsolutePath(), and makeAbsolute().
Returns true if the directory is the root directory; otherwise returns false.
Note: If the directory is a symbolic link to the root directory this function returns false. If you want to test for this use canonicalPath(), e.g.
QDir dir("/tmp/root_link"); dir = dir.canonicalPath(); if (dir.isRoot()) qWarning("It is a root link");
See also root() and rootPath().
Converts the directory path to an absolute path. If it is already absolute nothing happens. Returns true if the conversion succeeded; otherwise returns false.
See also isAbsolute(), isAbsolutePath(), isRelative(), and cleanPath().
Returns true if the fileName matches the wildcard (glob) pattern filter; otherwise returns false. The filter may contain multiple patterns separated by spaces or semicolons.
(See QRegExp wildcard matching.)
See also QRegExp::exactMatch(), entryList(), and entryInfoList().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns true if the fileName matches any of the wildcard (glob) patterns in the list of filters; otherwise returns false.
(See QRegExp wildcard matching.)
See also QRegExp::exactMatch(), entryList(), and entryInfoList().
Creates a directory.
If recurse is Recursive then subdirectories along the path to dirName will be created if necessary. If recurse is NonRecursive then is assumed that all subdirectories of dirName exist already.
If acceptAbsPath is true a path starting with a separator ('/') will create the absolute directory; if acceptAbsPath is false any number of separators at the beginning of dirName will be removed.
Returns true if successful; otherwise returns false.
See also rmdir().
Returns the string list set by setNameFilters()
Returns the path. This may contain symbolic links, but never contains redundant ".", ".." or multiple separators.
The returned path can be either absolute or relative (see setPath()).
See also setPath(), absolutePath(), exists(), cleanPath(), dirName(), absoluteFilePath(), convertSeparators(), and makeAbsolute().
Refreshes the directory information.
Removes the file, fileName.
If acceptAbsPath is true a path starting with separator "/" will remove the file with the absolute path. If acceptAbsPath is false any number of separators at the beginning of fileName will be removed and the resultant file name will be removed.
Returns true if the file is removed successfully; otherwise returns false.
Renames a file or directory.
If acceptAbsPaths is true a path starting with a separator ('/') will rename the file with the absolute path; if acceptAbsPaths is false any number of separators at the beginning of the names will be removed.
Returns true if successful; otherwise returns false.
On most file systems, rename() fails only if oldName does not exist or if newName and oldName are not on the same partition. On Windows, rename() will fail if newName already exists. However, there are also other reasons why rename() can fail. For example, on at least one file system rename() fails if newName points to an open file.
Removes the directory specified by dirName.
If recurse is Recursive then subdirectories along the path to dirName will be removed if they are empty. If recurse is NonRecursive then only the directory dirName will be removed.
If acceptAbsPath is true a path starting with a separator ('/') will remove the absolute directory; if acceptAbsPath is false any number of separators at the beginning of dirName will be removed.
The directory must be empty for rmdir() to succeed.
Returns true if successful; otherwise returns false.
See also mkdir().
Returns the root directory. See rootPath() for details.
See also drives(), current(), home(), and temp().
Returns the absolute path for the root directory.
For Unix operating systems this returns "/". For Windows file systems this normally returns "c:/".
See also root(), drives(), currentPath(), homePath(), and tempPath().
Returns the native directory separator: "/" under Unix (including Mac OS X) and "" under Windows.
You do not need to use this function to build file paths. If you always use "/", Qt will translate your paths to conform to the underlying operating system. If you want to display paths to the user using their operating system's separator use convertSeparators().
Sets the application's current working directory to path. Returns true if the directory was successfully changed; otherwise returns false.
See also current(), currentPath(), home(), root(), and temp().
Sets the name filter used by entryList() and entryInfoList() to nameFilters.
The nameFilters is a wildcard (globbing) filter that understands "*" and "?" wildcards. (See QRegExp wildcard matching.) You may specify several filter entries, each separated by spaces " ", or by semicolons ";".
For example, if you want entryList() and entryInfoList() to list all files ending with either ".cpp" or ".h", you would use either dir.setNameFilters("*.cpp *.h") or dir.setNameFilters("*.cpp;*.h").
See also nameFilters() and setFilter().
Sets the path of the directory to path. The path is cleaned of redundant ".", ".." and of multiple separators. No check is made to see whether a directory with this path actually exists; but you can check for yourself using exists().
The path can be either absolute or relative. Absolute paths begin with the directory separator "/" (optionally preceded by a drive specification under Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current directory. An example of an absolute path is the string "/tmp/quartz", a relative path might look like "src/fatlib".
See also path(), absolutePath(), exists(), cleanPath(), dirName(), absoluteFilePath(), isRelative(), and makeAbsolute().
Returns the value set by setSorting()
See also setSorting() and SortFlag.
Returns the system's temporary directory. See tempPath() for details.
See also drives(), currentPath(), homePath(), and rootPath().
Returns the system's temporary directory.
On Unix/Linux systems this is usually /tmp; on Windows this is usually the path in the TEMP or TMP environment variable.
See also temp(), drives(), currentPath(), homePath(), and rootPath().
Returns true if directory dir and this directory have different paths or different sort or filter settings; otherwise returns false.
Example:
// The current directory is "/usr/local" QDir d1("/usr/local/bin"); QDir d2("bin"); if (d1 != d2) qDebug("They differ");
Makes a copy of the dir object and assigns it to this QDir object.
Returns true if directory dir and this directory have the same path and their sort and filter settings are the same; otherwise returns false.
Example:
// The current directory is "/usr/local" QDir d1("/usr/local/bin"); QDir d2("bin"); if (d1 == d2) qDebug("They're the same");
Returns the file name at position pos in the list of file names. Equivalent to entryList().at(index).
Returns an empty string if pos is out of range or if the entryList() function failed.
See also count() and entryList().
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