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The QDir class provides access to directory structures and their contents in a platform-independent way. More...
All the functions in this class are reentrant when Qt is built with thread support.
#include <qdir.h>
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.
The "current" path refers to the application's working directory. A QDir's own path is set and retrieved with setPath() and path().
An example of an absolute path is the string "/tmp/quartz", a relative path might look like "src/fatlib". You can use the function isRelative() to check if a QDir is using a relative or an absolute file path. Call convertToAbs() to convert a relative QDir to an absolute one. For a simplified path use cleanDirPath(). 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().
QDir provides several static functions, for example, setCurrent() to set the application's working directory and currentDirPath() to retrieve the application's working directory. Access to some common paths is provided with the static functions, current(), home() and root() which return QDir objects or currentDirPath(), homeDirPath() and rootDirPath() which return the path as a string.
The number of entries in a directory is returned by count(). 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 setNameFilter(), setFilter() and setSorting(). They may also be specified in the entryList() and entryInfoList()'s arguments.
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 interrogate a directory with exists(), isReadable() and isRoot().
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 list of root directories is provided by drives(); on Unix systems this returns a list containing one root directory, "/"; on Windows the list will usually contain "C:/", and possibly "D:/", etc.
If you need the path in a form suitable for the underlying operating system use convertSeparators().
Examples:
See if a directory exists.
QDir d( "example" ); // "./example"
if ( !d.exists() )
qWarning( "Cannot find the example directory" );
Traversing directories and reading a file.
QDir d = QDir::root(); // "/"
if ( !d.cd("tmp") ) { // "/tmp"
qWarning( "Cannot find the \"/tmp\" directory" );
} else {
QFile f( d.filePath("ex1.txt") ); // "/tmp/ex1.txt"
if ( !f.open(IO_ReadWrite) )
qWarning( "Cannot create the file %s", f.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 d;
d.setFilter( QDir::Files | QDir::Hidden | QDir::NoSymLinks );
d.setSorting( QDir::Size | QDir::Reversed );
const QFileInfoList *list = d.entryInfoList();
QFileInfoListIterator it( *list );
QFileInfo *fi;
printf( " Bytes Filename\n" );
while ( (fi = it.current()) != 0 ) {
printf( "%10li %s\n", fi->size(), fi->fileName().latin1() );
++it;
}
return 0;
}
See also Input/Output and Networking.
This enum describes the filtering options available to QDir, e.g. for entryList() and entryInfoList(). The filter value is specified by OR-ing together values from the following list:
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.
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:
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.
See also currentDirPath().
The default nameFilter is an empty string, which excludes nothing; the default filterSpec is All, which also means exclude nothing. The default sortSpec is Name|IgnoreCase, i.e. sort by name case-insensitively.
Example that lists all the files in "/tmp":
QDir d( "/tmp" );
for ( int i = 0; i < d.count(); i++ )
printf( "%s\n", d[i] );
If path is "" or QString::null, QDir uses "." (the current directory). If nameFilter is "" or QString::null, QDir uses the name filter "*" (all files).
Note that path need not exist.
See also exists(), setPath(), setNameFilter(), setFilter(), and setSorting().
See also operator=().
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().
See also setPath(), canonicalPath(), exists(), cleanDirPath(), dirName(), and absFilePath().
Example: fileiconview/qfileiconview.cpp.
On systems that do not have symbolic links this function will always return the same string that absPath() returns. If the canonical path does not exist (normally due to dangling symbolic links) canonicalPath() returns QString::null.
See also path(), absPath(), exists(), cleanDirPath(), dirName(), absFilePath(), and QString::isNull().
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().
Example: fileiconview/mainwindow.cpp.
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().
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 absPath() and canonicalPath().
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 isRelative().
Equivalent to entryList().count().
See also operator[]() and entryList().
Use path() to access a QDir object's path.
See also currentDirPath() and QDir::QDir().
See also current().
Examples: helpviewer/helpwindow.cpp and qdir/qdir.cpp.
No check is made to ensure that a directory with this name actually exists.
See also path(), absPath(), absFilePath(), exists(), and QString::isNull().
The returned pointer is owned by Qt. Callers should not delete or modify it.
Example: dirview/main.cpp.
This function is included to easy porting from Qt 1.x to Qt 2.0, it is the same as entryList(), but encodes the filenames as 8-bit strings using QFile::encodedName().
It is more efficient to use entryList().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This function is included to easy porting from Qt 1.x to Qt 2.0, it is the same as entryList(), but encodes the filenames as 8-bit strings using QFile::encodedName().
It is more efficient to use entryList().
The filter and sorting specifications can be overridden using the nameFilter, filterSpec and sortSpec arguments.
Returns 0 if the directory is unreadable or does not exist.
The returned pointer is a const pointer to a QFileInfoList. The list is owned by the QDir object and will be reused on the next call to entryInfoList() for the same QDir instance. If you want to keep the entries of the list after a subsequent call to this function you must copy them.
See also entryList(), setNameFilter(), setSorting(), and setFilter().
Examples: dirview/dirview.cpp and fileiconview/qfileiconview.cpp.
Returns a list of QFileInfo objects for all the files and directories in the directory, ordered in accordance with setSorting() and filtered in accordance with setFilter() and setNameFilter().
The filter and sorting specifications can be overridden using the filterSpec and sortSpec arguments.
Returns 0 if the directory is unreadable or does not exist.
The returned pointer is a const pointer to a QFileInfoList. The list is owned by the QDir object and will be reused on the next call to entryInfoList() for the same QDir instance. If you want to keep the entries of the list after a subsequent call to this function you must copy them.
See also entryList(), setNameFilter(), setSorting(), and setFilter().
The filter and sorting specifications can be overridden using the nameFilter, filterSpec and sortSpec arguments.
Returns an empty list if the directory is unreadable or does not exist.
See also entryInfoList(), setNameFilter(), setSorting(), and setFilter().
Example: table/statistics/statistics.cpp.
Returns a list of the names of all the files and directories in the directory, ordered in accordance with setSorting() and filtered in accordance with setFilter() and setNameFilter().
The filter and sorting specifications can be overridden using the filterSpec and sortSpec arguments.
Returns an empty list if the directory is unreadable or does not exist.
See also entryInfoList(), setNameFilter(), setSorting(), and setFilter().
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.
Returns TRUE if the file exists; otherwise returns FALSE.
See also QFileInfo::exists() and QFile::exists().
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().
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 absFilePath(), isRelative(), and canonicalPath().
Returns the value set by setFilter()
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 rootDirPath() 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 rootDirPath() is used.
See also homeDirPath().
Returns the absolute path of the user's home directory.
See also home().
Warning: A FALSE value from this function is not a guarantee that files in the directory are not accessible.
See also QFileInfo::isReadable().
Examples: dirview/dirview.cpp and fileiconview/qfileiconview.cpp.
See also convertToAbs().
See also isRelative().
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 d( "/tmp/root_link" );
d = d.canonicalPath();
if ( d.isRoot() )
qWarning( "It is a root link" );
See also root() and rootDirPath().
(See QRegExp wildcard matching.)
See also QRegExp::match().
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::match().
Returns the value set by setMatchAllDirs()
See also setMatchAllDirs().
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 set by setNameFilter()
Returns TRUE if directory d 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" );
Sets the directory path to be the given path.
Example:
// The current directory is "/usr/local"
QDir d1( "/usr/local/bin" );
QDir d2( "bin" );
d2.convertToAbs();
if ( d1 == d2 )
qDebug( "They're the same" );
Returns a QString::null if the index is out of range or if the entryList() function failed.
See also count() and entryList().
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(), absPath(), exists(), cleanDirPath(), dirName(), absFilePath(), and convertSeparators().
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.
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.
Example: fileiconview/qfileiconview.cpp.
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().
See also rootDirPath() and drives().
For UNIX operating systems this returns "/". For Windows file systems this normally returns "c:/".
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.
See also filter() and setNameFilter().
See also matchAllDirs().
The nameFilter is a wildcard (globbing) filter that understands "*" and "?" wildcards. (See QRegExp wildcard matching.) You may specify several filter entries all separated by a single space " " or by a semi-colon ";".
For example, if you want entryList() and entryInfoList() to list all files ending with either ".cpp" or ".h", you would use either dir.setNameFilter("*.cpp *.h") or dir.setNameFilter("*.cpp;*.h").
See also nameFilter() and setFilter().
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(), absPath(), exists(), cleanDirPath(), dirName(), absFilePath(), isRelative(), and convertToAbs().
The sortSpec is specified by OR-ing values from the enum QDir::SortSpec.
See also sorting() and SortSpec.
Returns the value set by setSorting()
See also setSorting() and SortSpec.
This file is part of the Qt toolkit. Copyright © 1995-2003 Trolltech. All Rights Reserved.
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