The Q3Process 类用于启动外部程序并与之通信。 更多...
| 头： | #include <Q3Process> |
| 继承： | QObject |
| enum | Communication { Stdin, Stdout, Stderr, DupStderr } |
| Q3Process (QObject * parent = 0, const char * name = 0) | |
| Q3Process (const QString & arg0 , QObject * parent = 0, const char * name = 0) | |
| Q3Process (const QStringList & args , QObject * parent = 0, const char * name = 0) | |
| ~Q3Process () | |
| virtual void | addArgument (const QString & arg ) |
| QStringList | arguments () const |
| bool | canReadLineStderr () const |
| bool | canReadLineStdout () const |
| void | clearArguments () |
| int | communication () const |
| int | exitStatus () const |
| bool | isRunning () const |
| virtual bool | launch (const QByteArray & buf , QStringList * env = 0) |
| virtual bool | launch (const QString & buf , QStringList * env = 0) |
| bool | normalExit () const |
| PID | processIdentifier () |
| virtual QString | readLineStderr () |
| virtual QString | readLineStdout () |
| virtual QByteArray | readStderr () |
| virtual QByteArray | readStdout () |
| virtual void | setArguments (const QStringList & args ) |
| void | setCommunication (int commFlags ) |
| virtual void | setWorkingDirectory (const QDir & dir ) |
| virtual bool | start (QStringList * env = 0) |
| QDir | workingDirectory () const |
| virtual void | closeStdin () |
| void | kill () const |
| void | tryTerminate () const |
| virtual void | writeToStdin (const QByteArray & buf ) |
| virtual void | writeToStdin (const QString & buf ) |
| void | launchFinished () |
| void | processExited () |
| void | readyReadStderr () |
| void | readyReadStdout () |
| void | wroteToStdin () |
| virtual void | connectNotify (const char * signal ) |
| virtual void | disconnectNotify (const char * signal ) |
The Q3Process 类用于启动外部程序并与之通信。
You can write to the started program's standard input, and can read the program's standard output and standard error. You can pass command line arguments to the program either in the constructor or with setArguments () 或 addArgument (). The program's working directory can be set with setWorkingDirectory (). If you need to set up environment variables pass them to the start () 或 launch () functions (see below). The processExited () signal is emitted if the program exits. The program's exit status is available from exitStatus (), although you could simply call normalExit () to see if the program terminated normally.
There are two different ways to start a process. If you just want to run a program, optionally passing data to its standard input at the beginning, use one of the launch () functions. If you want full control of the program's standard input (especially if you don't know all the data you want to send to standard input at the beginning), use the start () 函数。
若使用 start () you can write to the program's standard input using writeToStdin () and you can close the standard input with closeStdin ()。 wroteToStdin () signal is emitted if the data sent to standard input has been written. You can read from the program's standard output using readStdout () 或 readLineStdout (). These functions return an empty QByteArray if there is no data to read. The readyReadStdout () signal is emitted when there is data available to be read from standard output. Standard error has a set of functions that correspond to the standard output functions, i.e. readStderr (), readLineStderr () 和 readyReadStderr ().
If you use one of the launch () functions the data you pass will be sent to the program's standard input which will be closed once all the data has been written. You should not 使用 writeToStdin () 或 closeStdin () if you use launch (). If you need to send data to the program's standard input after it has started running use start () 而不是 launch ().
Both start () 和 launch () can accept a string list of strings each of which has the format, key=value, where the keys are the names of environment variables.
You can test to see if a program is running with isRunning (). The program's process identifier is available from processIdentifier (). If you want to terminate a running program use tryTerminate (), but note that the program may ignore this. If you really want to terminate the program, without it having any chance to clean up, you can use kill ().
Although you may need quotes for a file named on the command line (e.g. if it contains spaces) you shouldn't use extra quotes for arguments passed to addArgument () 或 setArguments ().
The readyReadStdout () signal is emitted when there is new data on standard output. This happens asynchronously: you don't know if more data will arrive later.
In the above example you could connect the processExited () signal to the slot UicManager::readFromStdout() instead. If you do so, you will be certain that all the data is available when the slot is called. On the other hand, you must wait until the process has finished before doing any processing.
Note that if you are expecting a lot of output from the process, you may hit platform-dependent limits to the pipe buffer size. The solution is to make sure you connect to the output, e.g. the readyReadStdout () 和 readyReadStderr () signals and read the data as soon as it becomes available.
请注意 Q3Process does not emulate a shell. This means that Q3Process does not do any expansion of arguments: a '*' is passed as a '*' to the program and is not replaced by all the files, a '$HOME' is also passed literally and is not replaced by the environment variable HOME and the special characters for IO redirection ('>', '|', etc.) are also passed literally and do not have the special meaning as they have in a shell.
Also note that Q3Process does not emulate a terminal. This means that certain programs which need direct terminal control, do not work as expected with Q3Process . Such programs include console email programs (like pine and mutt) but also programs which require the user to enter a password (like su and ssh).
Some Windows commands, for example,
dir
, are not provided by separate applications, but by the command interpreter. If you attempt to use
Q3Process
to execute these commands directly it won't work. One possible solution is to execute the command interpreter itself (
cmd.exe
在某些 Windows 系统)，和要求解释器执行期望命令。
Under Windows there are certain problems starting 16-bit applications and capturing their output. Microsoft recommends using an intermediate application to start 16-bit applications.
另请参阅 Q3Socket .
This enum type defines the communication channels connected to the process.
| 常量 | 值 | 描述 |
|---|---|---|
Q3Process::Stdin
|
0x01
|
Data can be written to the process's standard input. |
Q3Process::Stdout
|
0x02
|
Data can be read from the process's standard output. |
Q3Process::Stderr
|
0x04
|
Data can be read from the process's standard error. |
Q3Process::DupStderr
|
0x08
|
Both the process's standard error output
and
its standard output are written to its standard output. (Like Unix's dup2().) This means that nothing is sent to the standard error output. This is especially useful if your application requires that the output on standard output and on standard error must be read in the same order that they are produced. This is a flag, so to activate it you must pass
Stdout|Stderr|DupStderr
，或
Stdin|Stdout|Stderr|DupStderr
if you want to provide input, to the
setCommunication
() 调用。
|
另请参阅 setCommunication () 和 communication ().
构造 Q3Process 对象。 parent and name parameters are passed to the QObject 构造函数。
另请参阅 setArguments (), addArgument ()，和 start ().
构造 Q3Process with arg0 as the command to be executed. The parent and name parameters are passed to the QObject 构造函数。
The process is not started. You must call start () 或 launch () to start the process.
另请参阅 setArguments (), addArgument ()，和 start ().
构造 Q3Process with args as the arguments of the process. The first element in the list is the command to be executed. The other elements in the list are the arguments to this command. The parent and name parameters are passed to the QObject 构造函数。
The process is not started. You must call start () 或 launch () to start the process.
另请参阅 setArguments (), addArgument ()，和 start ().
Destroys the instance.
If the process is running, it is <b>not</b> terminated! The standard input, standard output and standard error of the process are closed.
You can connect the destroyed () 信号到 kill () slot, if you want the process to be terminated automatically when the instance is destroyed.
另请参阅 tryTerminate () 和 kill ().
[虚拟]
void
Q3Process::
addArgument
(const
QString
&
arg
)
添加 arg to the end of the list of arguments.
The first element in the list of arguments is the command to be executed; the following elements are the command's arguments.
另请参阅 arguments () 和 setArguments ().
Returns the list of arguments that are set for the process. Arguments can be specified with the constructor or with the functions setArguments () 和 addArgument ().
Note that if you want to iterate over the list, you should iterate over a copy, e.g.
QStringList list = myProcess.arguments(); QStringList::Iterator it = list.begin(); while( it != list.end() ) { myProcessing( *it ); ++it; }
另请参阅 setArguments () 和 addArgument ().
Returns true if it's possible to read an entire line of text from standard error at this time; otherwise returns false.
另请参阅 readLineStderr () 和 canReadLineStdout ().
Returns true if it's possible to read an entire line of text from standard output at this time; otherwise returns false.
另请参阅 readLineStdout () 和 canReadLineStderr ().
Clears the list of arguments that are set for the process.
另请参阅 setArguments () 和 addArgument ().
[virtual slot]
void
Q3Process::
closeStdin
()
Closes the process's standard input.
This function also deletes any pending data that has not been written to standard input.
另请参阅 wroteToStdin ().
Returns the communication required with the process, i.e. some combination of the
Communication
flags.
另请参阅 setCommunication ().
[virtual protected]
void
Q3Process::
connectNotify
(const
char
*
signal
)
重实现自 QObject::connectNotify ().
[virtual protected]
void
Q3Process::
disconnectNotify
(const
char
*
signal
)
重实现自 QObject::disconnectNotify ().
Returns the exit status of the process or 0 if the process is still running. This function returns immediately and does not wait until the process is finished.
若 normalExit () is false (e.g. if the program was killed or crashed), this function returns 0, so you should check the return value of normalExit () before relying on this value.
另请参阅 normalExit () 和 processExited ().
Returns true if the process is running; otherwise returns false.
另请参阅 normalExit (), exitStatus ()，和 processExited ().
[slot]
void
Q3Process::
kill
() const
Terminates the process. This is not a safe way to end a process since the process will not be able to do any cleanup. tryTerminate () is safer, but processes can ignore a tryTerminate ().
The nice way to end a process and to be sure that it is finished, is to do something like this:
process->tryTerminate(); QTimer::singleShot( 5000, process, SLOT(kill()) );
This tries to terminate the process the nice way. If the process is still running after 5 seconds, it terminates the process the hard way. The timeout should be chosen depending on the time the process needs to do all its cleanup: use a higher value if the process is likely to do a lot of computation or I/O on cleanup.
The slot returns immediately: it does not wait until the process has finished. When the process terminates, the processExited () 信号发射。
另请参阅 tryTerminate () 和 processExited ().
[虚拟]
bool
Q3Process::
launch
(const
QByteArray
&
buf
,
QStringList
*
env
= 0)
Runs the process and writes the data buf to the process's standard input. If all the data is written to standard input, standard input is closed. The command is searched for in the path for executable programs; you can also use an absolute path in the command itself.
若
env
is null, then the process is started with the same environment as the starting process. If
env
is non-null, then the values in the string list are interpreted as environment setttings of the form
key=value
and the process is started with these environment settings. For convenience, there is a small exception to this rule under Unix: if
env
does not contain any settings for the environment variable
LD_LIBRARY_PATH
, then this variable is inherited from the starting process.
Returns true if the process could be started; otherwise returns false.
Note that you should not use the slots writeToStdin () 和 closeStdin () on processes started with launch(), since the result is not well-defined. If you need these slots, use start () 代替。
The process may or may not read the buf data sent to its standard input.
You can call this function even when a process that was started with this instance is still running. Be aware that if you do this the standard input of the process that was launched first will be closed, with any pending data being deleted, and the process will be left to run out of your control. Similarly, if the process could not be started the standard input will be closed and the pending data deleted. (On operating systems that have zombie processes, Qt will also wait() on the old process.)
The object emits the signal launchFinished () when this function call is finished. If the start was successful, this signal is emitted after all the data has been written to standard input. If the start failed, then this signal is emitted immediately.
另请参阅 start () 和 launchFinished ().
[虚拟]
bool
Q3Process::
launch
(const
QString
&
buf
,
QStringList
*
env
= 0)
这是重载函数。
The data buf is written to standard input with writeToStdin () 使用 QString::local8Bit () representation of the strings.
[signal]
void
Q3Process::
launchFinished
()
This signal is emitted when the process was started with launch (). If the start was successful, this signal is emitted after all the data has been written to standard input. If the start failed, then this signal is emitted immediately.
This signal is especially useful if you want to know when you can safely delete the Q3Process object when you are not interested in reading from standard output or standard error.
另请参阅 launch () 和 QObject::deleteLater ().
Returns true if the process has exited normally; otherwise returns false. This implies that this function returns false if the process is still running.
另请参阅 isRunning (), exitStatus ()，和 processExited ().
[signal]
void
Q3Process::
processExited
()
This signal is emitted when the process has exited.
另请参阅 isRunning (), normalExit (), exitStatus (), start ()，和 launch ().
Returns platform dependent information about the process. This can be used together with platform specific system calls.
Under Unix the return value is the PID of the process, or -1 if no process belongs to this object.
Under Windows it is a pointer to the
PROCESS_INFORMATION
struct, or 0 if no process is belongs to this object.
Use of this function's return value is likely to be non-portable.
[虚拟]
QString
Q3Process::
readLineStderr
()
Reads a line of text from standard error, excluding any trailing newline or carriage return characters and returns it. Returns an empty string if canReadLineStderr () 返回 false。
By default, the text is interpreted to be in Latin-1 encoding. If you need other codecs, you can set a different codec with QTextCodec::setCodecForCStrings ().
另请参阅 canReadLineStderr (), readyReadStderr (), readStderr ()，和 readLineStdout ().
[虚拟]
QString
Q3Process::
readLineStdout
()
Reads a line of text from standard output, excluding any trailing newline or carriage return characters, and returns it. Returns an empty string if canReadLineStdout () 返回 false。
By default, the text is interpreted to be in Latin-1 encoding. If you need other codecs, you can set a different codec with QTextCodec::setCodecForCStrings ().
另请参阅 canReadLineStdout (), readyReadStdout (), readStdout ()，和 readLineStderr ().
[虚拟]
QByteArray
Q3Process::
readStderr
()
Reads the data that the process has written to standard error. When new data is written to standard error, the class emits the signal readyReadStderr ().
If there is no data to read, this function returns a QByteArray of size 0: it does not wait until there is something to read.
另请参阅 readyReadStderr (), readLineStderr (), readStdout ()，和 writeToStdin ().
[虚拟]
QByteArray
Q3Process::
readStdout
()
Reads the data that the process has written to standard output. When new data is written to standard output, the class emits the signal readyReadStdout ().
If there is no data to read, this function returns a QByteArray of size 0: it does not wait until there is something to read.
另请参阅 readyReadStdout (), readLineStdout (), readStderr ()，和 writeToStdin ().
[signal]
void
Q3Process::
readyReadStderr
()
This signal is emitted when the process has written data to standard error. You can read the data with readStderr ().
Note that this signal is only emitted when there is new data and not when there is old, but unread data. In the slot connected to this signal, you should always read everything that is available at that moment to make sure that you don't lose any data.
另请参阅 readStderr (), readLineStderr ()，和 readyReadStdout ().
[signal]
void
Q3Process::
readyReadStdout
()
This signal is emitted when the process has written data to standard output. You can read the data with readStdout ().
Note that this signal is only emitted when there is new data and not when there is old, but unread data. In the slot connected to this signal, you should always read everything that is available at that moment to make sure that you don't lose any data.
另请参阅 readStdout (), readLineStdout ()，和 readyReadStderr ().
[虚拟]
void
Q3Process::
setArguments
(const
QStringList
&
args
)
集 args as the arguments for the process. The first element in the list is the command to be executed. The other elements in the list are the arguments to the command. Any previous arguments are deleted.
Q3Process
does not perform argument substitutions; for example, if you specify "*" or "$DISPLAY", these values are passed to the process literally. If you want to have the same behavior as the shell provides, you must do the substitutions yourself; i.e. instead of specifying a "*" you must specify the list of all the filenames in the current directory, and instead of "$DISPLAY" you must specify the value of the environment variable
DISPLAY
.
Note for Windows users. The standard Windows shells, e.g.
command.com
and
cmd.exe
, do not perform file globbing, i.e. they do not convert a "*" on the command line into a list of files in the current directory. For this reason most Windows applications implement their own file globbing, and as a result of this, specifying an argument of "*" for a Windows application is likely to result in the application performing a file glob and ending up with a list of filenames.
另请参阅 arguments () 和 addArgument ().
集 commFlags as the communication required with the process.
commFlags
is a bitwise OR of the flags defined by the
Communication
枚举。
默认为
Stdin|Stdout|Stderr
.
另请参阅 communication ().
[虚拟]
void
Q3Process::
setWorkingDirectory
(const
QDir
&
dir
)
集 dir as the working directory for processes. This does not affect running processes; only processes that are started afterwards are affected.
Setting the working directory is especially useful for processes that try to access files with relative paths.
另请参阅 workingDirectory () 和 start ().
[虚拟]
bool
Q3Process::
start
(
QStringList
*
env
= 0)
Tries to run a process for the command and arguments that were specified with setArguments (), addArgument () or that were specified in the constructor. The command is searched for in the path for executable programs; you can also use an absolute path in the command itself.
若
env
is null, then the process is started with the same environment as the starting process. If
env
is non-null, then the values in the stringlist are interpreted as environment setttings of the form
key=value
and the process is started in these environment settings. For convenience, there is a small exception to this rule: under Unix, if
env
does not contain any settings for the environment variable
LD_LIBRARY_PATH
, then this variable is inherited from the starting process; under Windows the same applies for the environment variable
PATH
.
Returns true if the process could be started; otherwise returns false.
You can write data to the process's standard input with writeToStdin (). You can close standard input with closeStdin () and you can terminate the process with tryTerminate (), or with kill ().
You can call this function even if you've used this instance to create a another process which is still running. In such cases, Q3Process closes the old process's standard input and deletes pending data, i.e., you lose all control over the old process, but the old process is not terminated. This applies also if the process could not be started. (On operating systems that have zombie processes, Qt will also wait() on the old process.)
另请参阅 launch () 和 closeStdin ().
[slot]
void
Q3Process::
tryTerminate
() const
Asks the process to terminate. Processes can ignore this if they wish. If you want to be certain that the process really terminates, you can use kill () 代替。
The slot returns immediately: it does not wait until the process has finished. When the process terminates, the processExited () 信号发射。
另请参阅 kill () 和 processExited ().
Returns the working directory that was set with setWorkingDirectory (), or the current directory if none has been explicitly set.
另请参阅 setWorkingDirectory () 和 QDir::current ().
[virtual slot]
void
Q3Process::
writeToStdin
(const
QByteArray
&
buf
)
Writes the data buf to the process's standard input. The process may or may not read this data.
This function returns immediately; the Q3Process class might write the data at a later point (you must enter the event loop for this to occur). When all the data is written to the process, the signal wroteToStdin () is emitted. This does not mean that the process actually read the data, since this class only detects when it was able to write the data to the operating system.
另请参阅 wroteToStdin (), closeStdin (), readStdout ()，和 readStderr ().
[virtual slot]
void
Q3Process::
writeToStdin
(const
QString
&
buf
)
这是重载函数。
字符串 buf is handled as text using the QString::local8Bit () representation.
[signal]
void
Q3Process::
wroteToStdin
()
This signal is emitted if the data sent to standard input (via writeToStdin ()) was actually written to the process. This does not imply that the process really read the data, since this class only detects when it was able to write the data to the operating system. But it is now safe to close standard input without losing pending data.
另请参阅 writeToStdin () 和 closeStdin ().