Can I cast the strTst* pt to an array of 2 pointers to strTst instance? with

strTst *pt = &Sp1;

although, there is a warning compiler issued. I get the address of the Sp1 array. I think since i get the address of a data object,then i can operate on the data object.

it's compiled, but with a warning, incompatible pointer types Initializating

typedef struct {
int s1;
int s2;
int s3
}strTst;

strTst spst1 = {3,5,7};

strTst spst2 = {1,2,4};

strTst *Sp1[2] =
{
&spst1,
&spst2
};

strTst *pt = &Sp1;

I wonder how can i use pt to get a value in spst2, I checked, (*pt) value = &spst1, *(pt+1) = &spst2. but the compiler not let me to use (*pt)->s1, or ( (strTst *)(*pt) )->s1

Thanks, First I think I don't need a synchronization. But when I code like:

//task A:
if (rcvd == true)
{
read rcv_buffer
...
rcvd = false;
}

//task B:
dataCB(int ch_id, char *buf, int len, char stat)
{
rcvd = true;
if((rcvd == false)
{
receivenotify(chid, rcv_buffer, sizeof(rcv_buffer), dataCB,0);
}
}

The program behavior is not correct

Thank you very much for the answer. But the C program is in an embedded device, it's not a pre-emptive task environment, just a forever loop cycle, in which, some functions be called in 10 ms cycle, some functions be called in 5 ms cycle. each cycle I called it a task. The structure like a simple scheduler using while(1) loop. Task A (or Cycle A) is a 10 ms cycle, and Task B is a 5 ms cycle, just use a counter to implemented the 10 ms , 5 ms cycle, like

while(1)
{
count ++;
if (count == 5)
{
task B be called
}
if (count == 10)
{
count = 0;
task A be called.
}
}

Thanks

no, no interrupts, it's a simple scheduler using while(1). and one cycle is 10 ms , one cycle is 5 ms. task A in 10 ms cycle, task B in 5 ms cycle.

No, its on a 32 bit micro controller, no OS.

It's a rare C program, no Events :)

Hi, I met a thread synchronization scenario in a small code.

//task A:
if (rcvd == true)
{
read rcv_buffer
...
rcvd = false;
}

//task B:
dataCB(int ch_id, char *buf, int len, char stat)
{
rcvd = true;
receivenotify(chid, rcv_buffer, sizeof(rcv_buffer), dataCB,0);
}

here, rcvd = false in task A, can't stop task B produce data. how can I let task A, B synchronized. add if (rcvd == false) in task B before receivenotify()? is that a dead lock ? Thanks

Thanks, I understood

is it similar to a pointer that points to an integer. like: int a = 0; int *ip = &a; then (ip+1) point to an integer too. but do we need to allocate memory space to it?

Thanks, I am reading the program. Just try to understand why a pointer to an array, be used as an array of vectors.

vector *adj; //adjacency list is it point to an Vector object?

Try to write a small program.almost forgot task sync concept, need some help. task1: if (cx == True) { do task1(); cx = False; } task2: if (cx == False) { do task2(); cx = True; } Is possible the 2 tasks step in a deadlock situation? Thanks

It's memory allocation problem. the MCU has 2 cpu inside, and one set of peripheral units, compiler put str123 in DMA Access prohibited area. Embedded programming, too many tricks. :)

It works. Yes, I think this is typical wild pointer.

Hi , I read a block of code, there is a function like:

void funcA( unsigned int * dtc, unsigned int* status)
{
int rval;
unsigned int* lstatus;
rval = funcB(dtc, lstatus);
.....
}

int funcB(unsigned int *idtc, unsinged int* istatus ) {
*istatus = XXX;
}

I understood, lstatus is not initialized, is that good way to use a local pointer like the above?

It's a GHS compiler. An embedded project.

But in the program, our system. It works. I tested it. just the caller.h: extern void A(void); I debugged the code, it stepped into the A(i); in fact, only one A() function in the program.

I read a program, a function definition like:

void A( int channel)
{
}

While the caller like:

A(); //no parameter here.

I know it's OK. can't find a explanation.