QProcess¶
The QProcess
class is used to start external programs and to communicate with them. More…
Synopsis¶
Functions¶
def
arguments
()def
closeReadChannel
(channel)def
closeWriteChannel
()def
environment
()def
error
()def
exitCode
()def
exitStatus
()def
inputChannelMode
()def
processChannelMode
()def
processEnvironment
()def
processId
()def
program
()def
readAllStandardError
()def
readAllStandardOutput
()def
readChannel
()def
setArguments
(arguments)def
setEnvironment
(environment)def
setInputChannelMode
(mode)def
setProcessChannelMode
(mode)def
setProcessEnvironment
(environment)def
setProcessState
(state)def
setProgram
(program)def
setReadChannel
(channel)def
setStandardErrorFile
(fileName[, mode=QIODeviceBase.OpenModeFlag.Truncate])def
setStandardInputFile
(fileName)def
setStandardOutputFile
(fileName[, mode=QIODeviceBase.OpenModeFlag.Truncate])def
setStandardOutputProcess
(destination)def
setWorkingDirectory
(dir)def
start
([mode=QIODeviceBase.OpenModeFlag.ReadWrite])def
start
(program[, arguments={}[, mode=QIODeviceBase.OpenModeFlag.ReadWrite]])def
startCommand
(command[, mode=QIODeviceBase.OpenModeFlag.ReadWrite])def
startDetached
([pid=None])def
state
()def
waitForFinished
([msecs=30000])def
waitForStarted
([msecs=30000])def
workingDirectory
()
Slots¶
Signals¶
def
errorOccurred
(error)def
finished
(exitCode[, exitStatus=QProcess.ExitStatus.NormalExit])
Static functions¶
def
execute
(program[, arguments={}])def
nullDevice
()def
splitCommand
(command)def
startDetached
(program[, arguments={}[, workingDirectory=””]])def
systemEnvironment
()
Detailed Description¶
Running a Process¶
To start a process, pass the name and command line arguments of the program you want to run as arguments to start()
. Arguments are supplied as individual strings in a QStringList
.
Alternatively, you can set the program to run with setProgram()
and setArguments()
, and then call start()
or open()
.
For example, the following code snippet runs the analog clock example in the Fusion style on X11 platforms by passing strings containing “-style” and “fusion” as two items in the list of arguments:
parent = QObject() ... program = "./path/to/Qt/examples/widgets/analogclock" arguments = QStringList() arguments << "-style" << "fusion" myProcess = QProcess(parent) myProcess.start(program, arguments)
QProcess
then enters the Starting
state, and when the program has started, QProcess
enters the Running
state and emits started()
.
QProcess
allows you to treat a process as a sequential I/O device. You can write to and read from the process just as you would access a network connection using QTcpSocket
. You can then write to the process’s standard input by calling write()
, and read the standard output by calling read()
, readLine()
, and getChar()
. Because it inherits QIODevice
, QProcess
can also be used as an input source for QXmlReader, or for generating data to be uploaded using QNetworkAccessManager
.
When the process exits, QProcess
reenters the NotRunning
state (the initial state), and emits finished()
.
The finished()
signal provides the exit code and exit status of the process as arguments, and you can also call exitCode()
to obtain the exit code of the last process that finished, and exitStatus()
to obtain its exit status. If an error occurs at any point in time, QProcess
will emit the errorOccurred()
signal. You can also call error()
to find the type of error that occurred last, and state()
to find the current process state.
Note
QProcess
is not supported on VxWorks, iOS, tvOS, or watchOS.
Communicating via Channels¶
Processes have two predefined output channels: The standard output channel (stdout
) supplies regular console output, and the standard error channel (stderr
) usually supplies the errors that are printed by the process. These channels represent two separate streams of data. You can toggle between them by calling setReadChannel()
. QProcess
emits readyRead()
when data is available on the current read channel. It also emits readyReadStandardOutput()
when new standard output data is available, and when new standard error data is available, readyReadStandardError()
is emitted. Instead of calling read()
, readLine()
, or getChar()
, you can explicitly read all data from either of the two channels by calling readAllStandardOutput()
or readAllStandardError()
.
The terminology for the channels can be misleading. Be aware that the process’s output channels correspond to QProcess
‘s read channels, whereas the process’s input channels correspond to QProcess
‘s write channels. This is because what we read using QProcess
is the process’s output, and what we write becomes the process’s input.
QProcess
can merge the two output channels, so that standard output and standard error data from the running process both use the standard output channel. Call setProcessChannelMode()
with MergedChannels
before starting the process to activate this feature. You also have the option of forwarding the output of the running process to the calling, main process, by passing ForwardedChannels
as the argument. It is also possible to forward only one of the output channels - typically one would use ForwardedErrorChannel
, but ForwardedOutputChannel
also exists. Note that using channel forwarding is typically a bad idea in GUI applications - you should present errors graphically instead.
Certain processes need special environment settings in order to operate. You can set environment variables for your process by calling setProcessEnvironment()
. To set a working directory, call setWorkingDirectory()
. By default, processes are run in the current working directory of the calling process.
The positioning and the screen Z-order of windows belonging to GUI applications started with QProcess
are controlled by the underlying windowing system. For Qt 5 applications, the positioning can be specified using the -qwindowgeometry
command line option; X11 applications generally accept a -geometry
command line option.
Note
On QNX, setting the working directory may cause all application threads, with the exception of the QProcess
caller thread, to temporarily freeze during the spawning process, owing to a limitation in the operating system.
Synchronous Process API¶
QProcess
provides a set of functions which allow it to be used without an event loop, by suspending the calling thread until certain signals are emitted:
waitForStarted()
blocks until the process has started.
waitForReadyRead()
blocks until new data is available for reading on the current read channel.
waitForBytesWritten()
blocks until one payload of data has been written to the process.
waitForFinished()
blocks until the process has finished.
Calling these functions from the main thread (the thread that calls exec()
) may cause your user interface to freeze.
The following example runs gzip
to compress the string “Qt rocks!”, without an event loop:
gzip = QProcess() gzip.start("gzip", QStringList() << "-c") if (not gzip.waitForStarted()) return False gzip.write("Qt rocks!") gzip.closeWriteChannel() if (not gzip.waitForFinished()) return False result = gzip.readAll()
Notes for Windows Users¶
Some Windows commands (for example, dir
) are not provided by separate applications, but by the command interpreter itself. If you attempt to use QProcess
to execute these commands directly, it won’t work. One possible solution is to execute the command interpreter itself (cmd.exe
on some Windows systems), and ask the interpreter to execute the desired command.
- class PySide6.QtCore.QProcess([parent=None])¶
- Parameters
parent –
PySide6.QtCore.QObject
Constructs a QProcess
object with the given parent
.
- PySide6.QtCore.QProcess.ProcessError¶
This enum describes the different types of errors that are reported by QProcess
.
Constant
Description
QProcess.FailedToStart
The process failed to start. Either the invoked program is missing, or you may have insufficient permissions or resources to invoke the program.
QProcess.Crashed
The process crashed some time after starting successfully.
QProcess.Timedout
The last waitFor…() function timed out. The state of
QProcess
is unchanged, and you can try calling waitFor…() again.QProcess.WriteError
An error occurred when attempting to write to the process. For example, the process may not be running, or it may have closed its input channel.
QProcess.ReadError
An error occurred when attempting to read from the process. For example, the process may not be running.
QProcess.UnknownError
An unknown error occurred. This is the default return value of
error()
.See also
- PySide6.QtCore.QProcess.ProcessState¶
This enum describes the different states of QProcess
.
Constant
Description
QProcess.NotRunning
The process is not running.
QProcess.Starting
The process is starting, but the program has not yet been invoked.
QProcess.Running
The process is running and is ready for reading and writing.
See also
- PySide6.QtCore.QProcess.ProcessChannel¶
This enum describes the process channels used by the running process. Pass one of these values to setReadChannel()
to set the current read channel of QProcess
.
Constant
Description
QProcess.StandardOutput
The standard output (stdout) of the running process.
QProcess.StandardError
The standard error (stderr) of the running process.
See also
- PySide6.QtCore.QProcess.ProcessChannelMode¶
This enum describes the process output channel modes of QProcess
. Pass one of these values to setProcessChannelMode()
to set the current read channel mode.
Constant
Description
QProcess.SeparateChannels
QProcess
manages the output of the running process, keeping standard output and standard error data in separate internal buffers. You can select theQProcess
‘s current read channel by callingsetReadChannel()
. This is the default channel mode ofQProcess
.QProcess.MergedChannels
QProcess
merges the output of the running process into the standard output channel (stdout
). The standard error channel (stderr
) will not receive any data. The standard output and standard error data of the running process are interleaved. For detached processes, the merged output of the running process is forwarded onto the main process.QProcess.ForwardedChannels
QProcess
forwards the output of the running process onto the main process. Anything the child process writes to its standard output and standard error will be written to the standard output and standard error of the main process.QProcess.ForwardedErrorChannel
QProcess
manages the standard output of the running process, but forwards its standard error onto the main process. This reflects the typical use of command line tools as filters, where the standard output is redirected to another process or a file, while standard error is printed to the console for diagnostic purposes. (This value was introduced in Qt 5.2.)QProcess.ForwardedOutputChannel
Complementary to . (This value was introduced in Qt 5.2.)
Note
Windows intentionally suppresses output from GUI-only applications to inherited consoles. This does not apply to output redirected to files or pipes. To forward the output of GUI-only applications on the console nonetheless, you must use and do the forwarding yourself by reading the output and writing it to the appropriate output channels.
See also
- PySide6.QtCore.QProcess.InputChannelMode¶
This enum describes the process input channel modes of QProcess
. Pass one of these values to setInputChannelMode()
to set the current write channel mode.
Constant
Description
QProcess.ManagedInputChannel
QProcess
manages the input of the running process. This is the default input channel mode ofQProcess
.QProcess.ForwardedInputChannel
QProcess
forwards the input of the main process onto the running process. The child process reads its standard input from the same source as the main process. Note that the main process must not try to read its standard input while the child process is running.See also
- PySide6.QtCore.QProcess.ExitStatus¶
This enum describes the different exit statuses of QProcess
.
Constant
Description
QProcess.NormalExit
The process exited normally.
QProcess.CrashExit
The process crashed.
See also
- PySide6.QtCore.QProcess.arguments()¶
- Return type
list of strings
Returns the command line arguments the process was last started with.
See also
- PySide6.QtCore.QProcess.closeReadChannel(channel)¶
- Parameters
channel –
ProcessChannel
Closes the read channel channel
. After calling this function, QProcess
will no longer receive data on the channel. Any data that has already been received is still available for reading.
Call this function to save memory, if you are not interested in the output of the process.
See also
- PySide6.QtCore.QProcess.closeWriteChannel()¶
Schedules the write channel of QProcess
to be closed. The channel will close once all data has been written to the process. After calling this function, any attempts to write to the process will fail.
Closing the write channel is necessary for programs that read input data until the channel has been closed. For example, the program “more” is used to display text data in a console on both Unix and Windows. But it will not display the text data until QProcess
‘s write channel has been closed. Example:
more = QProcess() more.start("more") more.write("Text to display") more.closeWriteChannel() # QProcess will emit readyRead() once "more" starts printing
The write channel is implicitly opened when start()
is called.
See also
- PySide6.QtCore.QProcess.environment()¶
- Return type
list of strings
Returns the environment that QProcess
will pass to its child process, or an empty QStringList
if no environment has been set using setEnvironment()
. If no environment has been set, the environment of the calling process will be used.
- PySide6.QtCore.QProcess.error()¶
- Return type
Returns the type of error that occurred last.
See also
- PySide6.QtCore.QProcess.errorOccurred(error)¶
- Parameters
error –
ProcessError
- static PySide6.QtCore.QProcess.execute(program[, arguments={}])¶
- Parameters
program – str
arguments – list of strings
- Return type
int
Starts the program program
with the arguments arguments
in a new process, waits for it to finish, and then returns the exit code of the process. Any data the new process writes to the console is forwarded to the calling process.
The environment and working directory are inherited from the calling process.
Argument handling is identical to the respective start()
overload.
If the process cannot be started, -2 is returned. If the process crashes, -1 is returned. Otherwise, the process’ exit code is returned.
See also
- PySide6.QtCore.QProcess.exitCode()¶
- Return type
int
Returns the exit code of the last process that finished.
This value is not valid unless exitStatus()
returns NormalExit
.
- PySide6.QtCore.QProcess.exitStatus()¶
- Return type
Returns the exit status of the last process that finished.
On Windows, if the process was terminated with TerminateProcess() from another application, this function will still return NormalExit
unless the exit code is less than 0.
- PySide6.QtCore.QProcess.finished(exitCode[, exitStatus=QProcess.ExitStatus.NormalExit])¶
- Parameters
exitCode – int
exitStatus –
ExitStatus
- PySide6.QtCore.QProcess.inputChannelMode()¶
- Return type
Returns the channel mode of the QProcess
standard input channel.
See also
setInputChannelMode()
InputChannelMode
- PySide6.QtCore.QProcess.kill()¶
Kills the current process, causing it to exit immediately.
On Windows, uses TerminateProcess, and on Unix and macOS, the SIGKILL signal is sent to the process.
See also
- static PySide6.QtCore.QProcess.nullDevice()¶
- Return type
str
The null device of the operating system.
The returned file path uses native directory separators.
- PySide6.QtCore.QProcess.processChannelMode()¶
- Return type
Returns the channel mode of the QProcess
standard output and standard error channels.
See also
setProcessChannelMode()
ProcessChannelMode
setReadChannel()
- PySide6.QtCore.QProcess.processEnvironment()¶
- Return type
Returns the environment that QProcess
will pass to its child process, or an empty object if no environment has been set using or setProcessEnvironment()
. If no environment has been set, the environment of the calling process will be used.
- PySide6.QtCore.QProcess.processId()¶
- Return type
int
Returns the native process identifier for the running process, if available. If no process is currently running, 0
is returned.
- PySide6.QtCore.QProcess.program()¶
- Return type
str
Returns the program the process was last started with.
See also
- PySide6.QtCore.QProcess.readAllStandardError()¶
- Return type
Regardless of the current read channel, this function returns all data available from the standard error of the process as a QByteArray
.
See also
readyReadStandardError()
readAllStandardOutput()
readChannel()
setReadChannel()
- PySide6.QtCore.QProcess.readAllStandardOutput()¶
- Return type
Regardless of the current read channel, this function returns all data available from the standard output of the process as a QByteArray
.
See also
readyReadStandardOutput()
readAllStandardError()
readChannel()
setReadChannel()
- PySide6.QtCore.QProcess.readChannel()¶
- Return type
Returns the current read channel of the QProcess
.
See also
- PySide6.QtCore.QProcess.setArguments(arguments)¶
- Parameters
arguments – list of strings
Set the arguments
to pass to the called program when starting the process. This function must be called before start()
.
See also
- PySide6.QtCore.QProcess.setEnvironment(environment)¶
- Parameters
environment – list of strings
Sets the environment that QProcess
will pass to the child process. The parameter environment
is a list of key=value pairs.
For example, the following code adds the environment variable TMPDIR
:
process = QProcess() env = QProcess.systemEnvironment() env << "TMPDIR=C:\\MyApp\\temp" # Add an environment variable process.setEnvironment(env) process.start("myapp")
Note
This function is less efficient than the setProcessEnvironment()
function.
- PySide6.QtCore.QProcess.setInputChannelMode(mode)¶
- Parameters
mode –
InputChannelMode
Sets the channel mode of the QProcess
standard input channel to the mode
specified. This mode will be used the next time start()
is called.
See also
inputChannelMode()
InputChannelMode
- PySide6.QtCore.QProcess.setProcessChannelMode(mode)¶
- Parameters
mode –
ProcessChannelMode
Sets the channel mode of the QProcess
standard output and standard error channels to the mode
specified. This mode will be used the next time start()
is called. For example:
builder = QProcess() builder.setProcessChannelMode(QProcess.MergedChannels) builder.start("make", QStringList() << "-j2") if not builder.waitForFinished(): print("Make failed:", builder.errorString()) else: print("Make output:", builder.readAll())See also
processChannelMode()
ProcessChannelMode
setReadChannel()
- PySide6.QtCore.QProcess.setProcessEnvironment(environment)¶
- Parameters
environment –
PySide6.QtCore.QProcessEnvironment
Sets the environment
that QProcess
will pass to the child process.
For example, the following code adds the environment variable TMPDIR
:
process = QProcess() env = QProcessEnvironment.systemEnvironment() env.insert("TMPDIR", "C:\\MyApp\\temp") # Add an environment variable process.setProcessEnvironment(env) process.start("myapp")
Note how, on Windows, environment variable names are case-insensitive.
- PySide6.QtCore.QProcess.setProcessState(state)¶
- Parameters
state –
ProcessState
Sets the current state of the QProcess
to the state
specified.
See also
- PySide6.QtCore.QProcess.setProgram(program)¶
- Parameters
program – str
Set the program
to use when starting the process. This function must be called before start()
.
See also
- PySide6.QtCore.QProcess.setReadChannel(channel)¶
- Parameters
channel –
ProcessChannel
Sets the current read channel of the QProcess
to the given channel
. The current input channel is used by the functions read()
, readAll()
, readLine()
, and getChar()
. It also determines which channel triggers QProcess
to emit readyRead()
.
See also
- PySide6.QtCore.QProcess.setStandardErrorFile(fileName[, mode=QIODeviceBase.OpenModeFlag.Truncate])¶
- Parameters
fileName – str
mode –
OpenMode
Redirects the process’ standard error to the file fileName
. When the redirection is in place, the standard error read channel is closed: reading from it using read()
will always fail, as will readAllStandardError()
. The file will be appended to if mode
is Append, otherwise, it will be truncated.
See setStandardOutputFile()
for more information on how the file is opened.
Note: if setProcessChannelMode()
was called with an argument of MergedChannels
, this function has no effect.
- PySide6.QtCore.QProcess.setStandardInputFile(fileName)¶
- Parameters
fileName – str
Redirects the process’ standard input to the file indicated by fileName
. When an input redirection is in place, the QProcess
object will be in read-only mode (calling write()
will result in error).
To make the process read EOF right away, pass nullDevice()
here. This is cleaner than using closeWriteChannel()
before writing any data, because it can be set up prior to starting the process.
If the file fileName
does not exist at the moment start()
is called or is not readable, starting the process will fail.
Calling after the process has started has no effect.
- PySide6.QtCore.QProcess.setStandardOutputFile(fileName[, mode=QIODeviceBase.OpenModeFlag.Truncate])¶
- Parameters
fileName – str
mode –
OpenMode
Redirects the process’ standard output to the file fileName
. When the redirection is in place, the standard output read channel is closed: reading from it using read()
will always fail, as will readAllStandardOutput()
.
To discard all standard output from the process, pass nullDevice()
here. This is more efficient than simply never reading the standard output, as no QProcess
buffers are filled.
If the file fileName
doesn’t exist at the moment start()
is called, it will be created. If it cannot be created, the starting will fail.
If the file exists and mode
is QIODevice::Truncate, the file will be truncated. Otherwise (if mode
is QIODevice::Append), the file will be appended to.
Calling after the process has started has no effect.
- PySide6.QtCore.QProcess.setStandardOutputProcess(destination)¶
- Parameters
destination –
PySide6.QtCore.QProcess
Pipes the standard output stream of this process to the destination
process’ standard input.
The following shell command:
command1 | command2
Can be accomplished with QProcess
with the following code:
process1 = QProcess() process2 = QProcess() process1.setStandardOutputProcess(process2) process1.start("command1") process2.start("command2")
- PySide6.QtCore.QProcess.setWorkingDirectory(dir)¶
- Parameters
dir – str
Sets the working directory to dir
. QProcess
will start the process in this directory. The default behavior is to start the process in the working directory of the calling process.
Note
On QNX, this may cause all application threads to temporarily freeze.
See also
- static PySide6.QtCore.QProcess.splitCommand(command)¶
- Parameters
command –
QStringView
- Return type
list of strings
Splits the string command
into a list of tokens, and returns the list.
Tokens with spaces can be surrounded by double quotes; three consecutive double quotes represent the quote character itself.
- PySide6.QtCore.QProcess.start([mode=QIODeviceBase.OpenModeFlag.ReadWrite])¶
- Parameters
mode –
OpenMode
This is an overloaded function.
Starts the program set by setProgram()
with arguments set by setArguments()
. The OpenMode is set to mode
.
See also
open()
setProgram()
setArguments()
- PySide6.QtCore.QProcess.start(program[, arguments={}[, mode=QIODeviceBase.OpenModeFlag.ReadWrite]])
- Parameters
program – str
arguments – list of strings
mode –
OpenMode
Starts the given program
in a new process, passing the command line arguments in arguments
.
The QProcess
object will immediately enter the Starting state. If the process starts successfully, QProcess
will emit started()
; otherwise, errorOccurred()
will be emitted.
Note
Processes are started asynchronously, which means the started()
and errorOccurred()
signals may be delayed. Call waitForStarted()
to make sure the process has started (or has failed to start) and those signals have been emitted.
Note
No further splitting of the arguments is performed.
Windows: The arguments are quoted and joined into a command line that is compatible with the CommandLineToArgvW()
Windows function. For programs that have different command line quoting requirements, you need to use setNativeArguments()
. One notable program that does not follow the CommandLineToArgvW()
rules is cmd.exe and, by consequence, all batch scripts.
The OpenMode is set to mode
.
If the QProcess
object is already running a process, a warning may be printed at the console, and the existing process will continue running unaffected.
See also
processId()
started()
waitForStarted()
setNativeArguments()
- PySide6.QtCore.QProcess.startCommand(command[, mode=QIODeviceBase.OpenModeFlag.ReadWrite])¶
- Parameters
command – str
mode –
OpenMode
Starts the command command
in a new process. The OpenMode is set to mode
.
command
is a single string of text containing both the program name and its arguments. The arguments are separated by one or more spaces. For example:
process = QProcess() process.startCommand("del /s *.txt") # same as process.start("del", QStringList() << "/s" << "*.txt") ...
Arguments containing spaces must be quoted to be correctly supplied to the new process. For example:
process = QProcess() process.startCommand("dir \"My Documents\"")
Literal quotes in the command
string are represented by triple quotes. For example:
process = QProcess() process.startCommand("dir \"Epic 12\"\"\" Singles\"")
After the command
string has been split and unquoted, this function behaves like start()
.
On operating systems where the system API for passing command line arguments to a subprocess natively uses a single string (Windows), one can conceive command lines which cannot be passed via QProcess
‘s portable list-based API. In these rare cases you need to use setProgram()
and setNativeArguments()
instead of this function.
See also
- static PySide6.QtCore.QProcess.startDetached(program[, arguments={}[, workingDirectory=""]])¶
- Parameters
program – str
arguments – list of strings
workingDirectory – str
- Return type
(retval, pid)
This function overloads startDetached()
.
Starts the program program
with the arguments arguments
in a new process, and detaches from it. Returns true
on success; otherwise returns false
. If the calling process exits, the detached process will continue to run unaffected.
Argument handling is identical to the respective start()
overload.
The process will be started in the directory workingDirectory
. If workingDirectory
is empty, the working directory is inherited from the calling process.
If the function is successful then *``pid`` is set to the process identifier of the started process.
See also
- PySide6.QtCore.QProcess.startDetached([pid=None])
- Parameters
pid – int
- Return type
bool
Starts the program set by setProgram()
with arguments set by setArguments()
in a new process, and detaches from it. Returns true
on success; otherwise returns false
. If the calling process exits, the detached process will continue to run unaffected.
Unix: The started process will run in its own session and act like a daemon.
The process will be started in the directory set by setWorkingDirectory()
. If workingDirectory()
is empty, the working directory is inherited from the calling process.
Note
On QNX, this may cause all application threads to temporarily freeze.
If the function is successful then *``pid`` is set to the process identifier of the started process; otherwise, it’s set to -1. Note that the child process may exit and the PID may become invalid without notice. Furthermore, after the child process exits, the same PID may be recycled and used by a completely different process. User code should be careful when using this variable, especially if one intends to forcibly terminate the process by operating system means.
Only the following property setters are supported by :
setCreateProcessArgumentsModifier()
setNativeArguments()
setProcessChannelMode
(MergedChannels
)
All other properties of the QProcess
object are ignored.
Note
The called process inherits the console window of the calling process. To suppress console output, redirect standard/error output to nullDevice()
.
See also
start()
startDetached(const QString &program, const QStringList &arguments, const QString &workingDirectory, qint64 *pid)
- PySide6.QtCore.QProcess.state()¶
- Return type
Returns the current state of the process.
See also
stateChanged()
error()
- static PySide6.QtCore.QProcess.systemEnvironment()¶
- Return type
list of strings
Returns the environment of the calling process as a list of key=value pairs. Example:
environment = QProcess.systemEnvironment() # environment = {"PATH=/usr/bin:/usr/local/bin", # "USER=greg", "HOME=/home/greg"}
This function does not cache the system environment. Therefore, it’s possible to obtain an updated version of the environment if low-level C library functions like setenv
or putenv
have been called.
However, note that repeated calls to this function will recreate the list of environment variables, which is a non-trivial operation.
Note
For new code, it is recommended to use systemEnvironment()
- PySide6.QtCore.QProcess.terminate()¶
Attempts to terminate the process.
The process may not exit as a result of calling this function (it is given the chance to prompt the user for any unsaved files, etc).
On Windows, posts a WM_CLOSE message to all top-level windows of the process and then to the main thread of the process itself. On Unix and macOS the SIGTERM
signal is sent.
Console applications on Windows that do not run an event loop, or whose event loop does not handle the WM_CLOSE message, can only be terminated by calling kill()
.
See also
- PySide6.QtCore.QProcess.waitForFinished([msecs=30000])¶
- Parameters
msecs – int
- Return type
bool
Blocks until the process has finished and the finished()
signal has been emitted, or until msecs
milliseconds have passed.
Returns true
if the process finished; otherwise returns false
(if the operation timed out, if an error occurred, or if this QProcess
is already finished).
This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread.
Warning
Calling this function from the main (GUI) thread might cause your user interface to freeze.
If msecs is -1, this function will not time out.
See also
finished()
waitForStarted()
waitForReadyRead()
waitForBytesWritten()
- PySide6.QtCore.QProcess.waitForStarted([msecs=30000])¶
- Parameters
msecs – int
- Return type
bool
Blocks until the process has started and the started()
signal has been emitted, or until msecs
milliseconds have passed.
Returns true
if the process was started successfully; otherwise returns false
(if the operation timed out or if an error occurred).
This function can operate without an event loop. It is useful when writing non-GUI applications and when performing I/O operations in a non-GUI thread.
Warning
Calling this function from the main (GUI) thread might cause your user interface to freeze.
If msecs is -1, this function will not time out.
Note
On some UNIX operating systems, this function may return true but the process may later report a FailedToStart
error.
See also
started()
waitForReadyRead()
waitForBytesWritten()
waitForFinished()
- PySide6.QtCore.QProcess.workingDirectory()¶
- Return type
str
If QProcess
has been assigned a working directory, this function returns the working directory that the QProcess
will enter before the program has started. Otherwise, (i.e., no directory has been assigned,) an empty string is returned, and QProcess
will use the application’s current working directory instead.
See also
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