Multithreading

[Enrico Maria Giordano]

Antonio,

what do you think about this sample (xHarbour):

Code: Select all  Expand view

FUNCTION MAIN()

    LOCAL hThr := STARTTHREAD( @MyFunc() )

    INKEY( 0 )

    STOPTHREAD( hThr )

    INKEY( 0 )

    RETURN NIL


STATIC FUNCTION MYFUNC()

    WHILE .T.
        THREADSLEEP( 1000 )
        TONE( 440, 1 )
    ENDDO

    RETURN NIL

EMG

[Silvio.Falconi]

what I can do with it ?

[Antonio Linares]

Enrico,

It seems what you were looking for

Does it work fine ?

[Enrico Maria Giordano]

Silvio,

what I can do with it ?

I'm experimenting a way to make wait animations smooth even with loops without SysRefresh() inside them.

EMG

[Enrico Maria Giordano]

Antonio,

Enrico,

It seems what you were looking for

Does it work fine ?

It seems so.

EMG

[Enrico Maria Giordano]

I just found that MT EXEs are slower than ST ones.

Any comments?

EMG

[Antonio Linares]

Enrico,

How have you measured it ?

[Enrico Maria Giordano]

Antonio,

Enrico,

How have you measured it ?

With Seconds(). What else?

EMG

[Antonio Linares]

Could you provide a small example of what you tested ? thanks

[Enrico Maria Giordano]

Antonio,

Could you provide a small example of what you tested ? thanks

Something like this:

Code: Select all  Expand view

FUNCTION MAIN()

    LOCAL nSec

    LOCAL cVal

    USE MYTABLE

    nSec = SECONDS()

    WHILE !EOF()
        cVal = FIELD -> myfield
        SKIP
    ENDDO

    ? "Assign and skip", SECONDS() - nSec

    CLOSE

    INKEY( 0 )

    RETURN NIL

Here I get ST: 31 MT: 41!

EMG

[StefanHaupt]

Enrico,

just to understand, what could be the advantages using MT instead of ST ? What functions could be put in threads ?

Im my understanding a database application is a single thread application with single tasks, e.g. browsing a dbf or searching in a dbf. What can be done, to get simultaneous tasks ?

Stefan

[Enrico Maria Giordano]

Stefan,

Enrico,

just to understand, what could be the advantages using MT instead of ST ? What functions could be put in threads ?

Im my understanding a database application is a single thread application with single tasks, e.g. browsing a dbf or searching in a dbf. What can be done, to get simultaneous tasks ?

Stefan

Don't know. I just need something to get smooth wait animations during loops without SysRefresh() in them.

EMG

[Antonio Linares]

Enrico,

Thanks for your example, what source code had you running on the second thread ?

[Enrico Maria Giordano]

Antonio,

Enrico,

Thanks for your example, what source code had you running on the second thread ?

Nothing. I created no threads. Just link vmmt.lib and cw32mt.lib in.

EMG

[Antonio Linares]

Enrico,

How many records you have on the DBF ?