qfileinfo.3qt

qt专门用于嵌入式的图形开发GUI

'\" t
.TH QFileInfo 3qt "2 September 2005" "Trolltech AS" \" -*- nroff -*-
.\" Copyright 1992-2001 Trolltech AS.  All rights reserved.  See the
.\" license file included in the distribution for a complete license
.\" statement.
.\"
.ad l
.nh
.SH NAME
QFileInfo \- System-independent file information
.SH SYNOPSIS
All the functions in this class are reentrant when Qt is built with thread support.</p>
.PP
\fC#include <qfileinfo.h>\fR
.PP
.SS "Public Members"
.in +1c
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.BI "enum \fBPermissionSpec\fR { ReadOwner = 04000, WriteOwner = 02000, ExeOwner = 01000, ReadUser = 00400, WriteUser = 00200, ExeUser = 00100, ReadGroup = 00040, WriteGroup = 00020, ExeGroup = 00010, ReadOther = 00004, WriteOther = 00002, ExeOther = 00001 }"
.br
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.BI "\fBQFileInfo\fR ()"
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.BI "\fBQFileInfo\fR ( const QString & file )"
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.BI "\fBQFileInfo\fR ( const QFile & file )"
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.BI "\fBQFileInfo\fR ( const QDir & d, const QString & fileName )"
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.BI "\fBQFileInfo\fR ( const QFileInfo & fi )"
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.BI "\fB~QFileInfo\fR ()"
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.BI "QFileInfo & \fBoperator=\fR ( const QFileInfo & fi )"
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.BI "void \fBsetFile\fR ( const QString & file )"
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.BI "void \fBsetFile\fR ( const QFile & file )"
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.BI "void \fBsetFile\fR ( const QDir & d, const QString & fileName )"
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.BI "bool \fBexists\fR () const"
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.BI "void \fBrefresh\fR () const"
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.BI "bool \fBcaching\fR () const"
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.BI "void \fBsetCaching\fR ( bool enable )"
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.BI "QString \fBfilePath\fR () const"
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.BI "QString \fBfileName\fR () const"
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.BI "QString \fBabsFilePath\fR () const"
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.BI "QString \fBbaseName\fR ( bool complete = FALSE ) const"
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.BI "QString \fBextension\fR ( bool complete = TRUE ) const"
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.BI "QString \fBdirPath\fR ( bool absPath = FALSE ) const"
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.BI "QDir \fBdir\fR ( bool absPath = FALSE ) const"
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.BI "bool \fBisReadable\fR () const"
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.BI "bool \fBisWritable\fR () const"
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.BI "bool \fBisExecutable\fR () const"
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.BI "bool \fBisHidden\fR () const"
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.BI "bool \fBisRelative\fR () const"
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.BI "bool \fBconvertToAbs\fR ()"
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.BI "bool \fBisFile\fR () const"
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.BI "bool \fBisDir\fR () const"
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.BI "bool \fBisSymLink\fR () const"
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.BI "QString \fBreadLink\fR () const"
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.BI "QString \fBowner\fR () const"
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.BI "uint \fBownerId\fR () const"
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.BI "QString \fBgroup\fR () const"
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.BI "uint \fBgroupId\fR () const"
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.BI "bool \fBpermission\fR ( int permissionSpec ) const"
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.BI "uint \fBsize\fR () const"
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.BI "QDateTime \fBcreated\fR () const"
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.BI "QDateTime \fBlastModified\fR () const"
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.BI "QDateTime \fBlastRead\fR () const"
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.in -1c
.SH DESCRIPTION
The QFileInfo class provides system-independent file information.
.PP
QFileInfo provides information about a file's name and position (path) in the file system, its access rights and whether it is a directory or symbolic link, etc. The file's size and last modified/read times are also available.
.PP
A QFileInfo can point to a file with either a relative or an absolute file path. Absolute file paths begin with the directory separator "/" (or with a drive specification on Windows). Relative file names begin with a directory name or a file name and specify a path relative to the current working directory. 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 whether a QFileInfo is using a relative or an absolute file path. You can call the function convertToAbs() to convert a relative QFileInfo's path to an absolute path.
.PP
The file that the QFileInfo works on is set in the constructor or later with setFile(). Use exists() to see if the file exists and size() to get its size.
.PP
To speed up performance, QFileInfo caches information about the file. Because files can be changed by other users or programs, or even by other parts of the same program, there is a function that refreshes the file information: refresh(). If you want to switch off a QFileInfo's caching and force it to access the file system every time you request information from it call setCaching(FALSE).
.PP
The file's type is obtained with isFile(), isDir() and isSymLink(). The readLink() function provides the name of the file the symlink points to.
.PP
Elements of the file's name can be extracted with dirPath() and fileName(). The fileName()'s parts can be extracted with baseName() and extension().
.PP
The file's dates are returned by created(), lastModified() and lastRead(). Information about the file's access permissions is obtained with isReadable(), isWritable() and isExecutable(). The file's ownership is available from owner(), ownerId(), group() and groupId(). You can examine a file's permissions and ownership in a single statement using the permission() function.
.PP
If you need to read and traverse directories, see the QDir class.
.PP
See also Input/Output and Networking.
.SS "Member Type Documentation"
.SH "QFileInfo::PermissionSpec"
This enum is used by the permission() function to report the permissions and ownership of a file. The values may be OR-ed together to test multiple permissions and ownership values.
.TP
\fCQFileInfo::ReadOwner\fR - The file is readable by the owner of the file.
.TP
\fCQFileInfo::WriteOwner\fR - The file is writable by the owner of the file.
.TP
\fCQFileInfo::ExeOwner\fR - The file is executable by the owner of the file.
.TP
\fCQFileInfo::ReadUser\fR - The file is readable by the user.
.TP
\fCQFileInfo::WriteUser\fR - The file is writable by the user.
.TP
\fCQFileInfo::ExeUser\fR - The file is executable by the user.
.TP
\fCQFileInfo::ReadGroup\fR - The file is readable by the group.
.TP
\fCQFileInfo::WriteGroup\fR - The file is writable by the group.
.TP
\fCQFileInfo::ExeGroup\fR - The file is executable by the group.
.TP
\fCQFileInfo::ReadOther\fR - The file is readable by anyone.
.TP
\fCQFileInfo::WriteOther\fR - The file is writable by anyone.
.TP
\fCQFileInfo::ExeOther\fR - The file is executable by anyone.
.PP
\fBWarning:\fR The semantics of ReadUser, WriteUser and ExeUser are unfortunately not platform independent: on Unix, the rights of the owner of the file are returned and on Windows the rights of the current user are returned. This behavior might change in a future Qt version. If you want to find the rights of the owner of the file, you should use the flags ReadOwner, WriteOwner and ExeOwner. If you want to find out the rights of the current user, you should use isReadable(), isWritable() and isExecutable().
.SH MEMBER FUNCTION DOCUMENTATION
.SH "QFileInfo::QFileInfo ()"
Constructs a new empty QFileInfo.
.SH "QFileInfo::QFileInfo ( const QString & file )"
Constructs a new QFileInfo that gives information about the given file. The \fIfile\fR can also include an absolute or relative path.
.PP
\fBWarning:\fR Some functions might behave in a counter-intuitive way if \fIfile\fR has a trailing directory separator.
.PP
See also setFile(), isRelative(), QDir::setCurrent(), and QDir::isRelativePath().
.SH "QFileInfo::QFileInfo ( const QFile & file )"
Constructs a new QFileInfo that gives information about file \fIfile\fR.
.PP
If the \fIfile\fR has a relative path, the QFileInfo will also have a relative path.
.PP
See also isRelative().
.SH "QFileInfo::QFileInfo ( const QDir & d, const QString & fileName )"
Constructs a new QFileInfo that gives information about the file called \fIfileName\fR in the directory \fId\fR.
.PP
If \fId\fR has a relative path, the QFileInfo will also have a relative path.
.PP
See also isRelative().
.SH "QFileInfo::QFileInfo ( const QFileInfo & fi )"
Constructs a new QFileInfo that is a copy of \fIfi\fR.
.SH "QFileInfo::~QFileInfo ()"
Destroys the QFileInfo and frees its resources.
.SH "QString QFileInfo::absFilePath () const"
Returns the absolute path including the file name.
.PP
The absolute path name consists of the full path and the file name. On Unix this will always begin with the root, '/', directory. On Windows this will always begin 'D:/' where D is a drive letter, except for network shares that are not mapped to a drive letter, in which case the path will begin '//sharename/'.
.PP
This function returns the same as filePath(), unless isRelative() is TRUE.
.PP
If the QFileInfo is empty it returns QDir::currentDirPath().
.PP
This function can be time consuming under Unix (in the order of milliseconds).
.PP
See also isRelative() and filePath().
.PP
Example: fileiconview/qfileiconview.cpp.
.SH "QString QFileInfo::baseName ( bool complete = FALSE ) const"
Returns the base name of the file.
.PP
If \fIcomplete\fR is FALSE (the default) the base name consists of all characters in the file name up to (but not including) the \fIfirst\fR '.' character.
.PP
If \fIcomplete\fR is TRUE the base name consists of all characters in the file up to (but not including) the \fIlast\fR '.' character.
.PP
The path is not included in either case.
.PP
Example:
.PP
.nf
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        QFileInfo fi( "/tmp/archive.tar.gz" );
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        QString base = fi.baseName();  // base = "archive"
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        base = fi.baseName( TRUE );    // base = "archive.tar"
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.fi
.PP
See also fileName() and extension().
.SH "bool QFileInfo::caching () const"
Returns TRUE if caching is enabled; otherwise returns FALSE.
.PP
See also setCaching() and refresh().
.SH "bool QFileInfo::convertToAbs ()"
Converts the file's path to an absolute path.
.PP
If it is already absolute, nothing is done.
.PP
See also filePath() and isRelative().
.SH "QDateTime QFileInfo::created () const"
Returns the date and time when the file was created.
.PP
On platforms where this information is not available, returns the same as lastModified().
.PP