Ren Yuhong wrote:
> Dear All,
>
> I am combining Qt & RT Linux to develpe a simple motor controller. I use
> Qt to design a GUI, since I need to use RT FIFO for communication
> between Qt's GUI and the real time kernel module, I need to handle the
> RT FIFO within GUI, following is my codes:
>
> ---------------------------------------------
> /********************
> Constructor
> NB: "TEST" is a dialog
> *********************/
> TestImpl::TestImpl( QWidget* parent,const char* name, bool modal, WFlags
> f) : TEST( parent, name, modal,f)
> {
>
> // Try to connect with RT task via FIFO
> fd1 = open("/dev/rtf1", O_RDWR);
> if ( fd1 == -1 )
> {
> printf("Can not open /dev/rtf1\n");
> close(fd1);
> //return -1;
> }
>
> fd2 = open("/dev/rtf2", O_RDWR); //RDWR
> if ( fd2 == -1 )
> {
> printf("Can not open /dev/rtf2\n");
> close(fd2);
> //return -1;
> }
> }
>
> ------------------------------------------------
> /***********
> Destructor
> ***********/
> TestImpl:: ~TestImpl()
> {
> close(fd1);
> close(fd2);
> }
> -----------------------------------------------
>
> With the above constructor and destructor, it is Ok to open the dialog
> class only ONCE within my GUI. If I open it for the second time, the
> error message comes out as follows:
> --------------
> QGArray: Cannot allocate array with negative length
> Segmentation fault (core dumped)
> --------------
>
> I am wondering if the RT FIFOs have really been closed or not. I used
> RHIDE to debug it, and found that the codes went through "close(fd1);
> close(fd2);".
>
Why do you suspect the FIFO's when you're error message is complaining
about QGArray code? Have you tried gdb to see where the seg fault occurs?
--Gordon
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