I am trying to create a graphics library. I need to:
int NewDisplay(Display **display, DisplayClass dispClass, int xRes, int yRes)
{
/* create a display:
-- allocate memory for indicated class and resolution
-- pass back pointer to Display object in display
*/
return SUCCESS;
}
How can I allocate memory to class and to the resolution?
Let me guess:
int NewDisplay(Display **display, DisplayClass dispClass, int xRes, int yRes)
{
(*display) = new Display( dispClass, xRes, yRes );
return SUCCESS;
}
If you need to get all the server side memory details,
http://brigitzblog.blogspot.com/2011/11/jspservlet-display-server-memory.html
Related
I have two int values:
v_y
v_x
That I would like to convert to a size 2 char array then write to my serial port.
I currently have this code that isn't working:
void Array2 (char charArray[], int sizeOfArray);
........
}
{
char one[] = { 'v_x', 'v_y' };
Array2(one, 2);
Serial::WriteData(one, 2);
}
}
I currently get two errors:
a nonstatic member reference must be relative to a specific object
and
'Serial::WriteData':illegal call of non-static member function.
Any help, hint or idea on what I'm doing wrong would be great!
Edit: I'm using this code to communicate with my serialport CODE
// data.h or similar, you need this for both the arduino and desktop machine
struct Data {
double v_x;
double v_y;
}
On your arduino: To write
Data data = {
.v_x = 1.0, // Example put your values here
.v_y = 2.0,
};
// This should write from your Arduino to the computer
Serial::WriteData((const char*)data, sizeof(data));
On your computer
Data data;
// This reads from the serial port, and put the data in the struct
auto len = SP->ReadData((const char*)data, sizeof(data));
// check that data is the right size
// use the data from data.v_x and data.v_y
auto v_x = data.v_x;
auto v_y = data.v_y; // etc
I want to create an object on the device and allocate it to a pointer available on the host. Is there something I'm doing wrong in here?
__global__ void createAProduction(DeviceProduction* production) {
production = new AProduction();
}
DeviceProduction * devAProduction = NULL;
cudaMalloc(&devAProduction, sizeof(AProduction));
createAProduction<<<1, 1>>>(devAProduction);
deviceProductions["A"] = devAProduction;
Somewhere further in the code I'd like to do sth. like:
BatchOperation ** devBatchOperations;
cudaMalloc((void **) &devBatchOperations, sizeof(BatchOperation *) * operationCount);
Then I populate that pointer array with that:
void DeviceBatchExecutor::execute(vector<BatchOperation> operationsToPerform) {
BatchOperation ** devBatchOperations;
cudaMalloc((void **) &devBatchOperations, sizeof(BatchOperation *) * operationsToPerform.size());
int i = 0;
for(batchOperationIt it = operationsToPerform.begin(); it != operationsToPerform.end(); ++it) {
BatchOperation * devBatchOperation;
cudaMalloc(&devBatchOperation, sizeof(BatchOperation));
cudaMemcpy(&devBatchOperation, &it, sizeof(BatchOperation), cudaMemcpyHostToDevice);
Vertex * devInputNode = it->inputNode->allocateToDevice();
cudaMemcpy(&(devBatchOperation->inputNode), &devInputNode, sizeof(Vertex *), cudaMemcpyDeviceToDevice);
cudaMemcpy(&(devBatchOperation->production), &(it->production), sizeof(Production *), cudaMemcpyDeviceToDevice);
cudaMemcpy(&devBatchOperations[i], &devBatchOperation, sizeof(BatchOperation *), cudaMemcpyDeviceToDevice);
i++;
}
int operationCount = operationsToPerform.size();
executeOperations<<<operationCount, 1>>>(devBatchOperations);
}
where production is a pointer to the device memory holding that created object AProduction. Then I finally invoke processing via
executeOperations<<<operationCount, 1>>>(devBatchOperations);
So I'm relying on virtual method calls. As those DeviceProduction objects were created on the device, there is also a virtual pointer table so it should work. See example here. But it doesn't since the received batch operations seem random... crashes on invocation.
__global__ void executeOperations(BatchOperation ** operation) {
operation[blockIdx.x]->production->apply(operation[blockIdx.x]->inputNode);
}
Batch operation is a struct holding the production to be executed.
struct BatchOperation {
Production * production;
Vertex * inputNode;
Vertex * outputNode;
};
Is there something I'm doing wrong in here?
Yes, probably. The pointer production is passed to the kernel by value:
createAProduction<<<1, 1>>>(devAProduction);
It points to a location in device memory somewhere, since you've already run cudaMalloc on it. This line of kernel code:
production = new AProduction();
overwrites the pass-by-value copy of the production pointer with a new one, returned by in-kernel new. That is almost certainly not what you had intended. (And you haven't defined what AProduction is.). At the completion of that kernel call, the pass-by-value "copy" of the pointer will be lost anyway. You might be able to fix it like this:
*production = *(new DeviceProduction());
Now your production pointer points to a region in device memory that holds an instantiated (on the device) object, which appears to be your intent there. Creating a new object just to copy it may not be necessary, but that is not the crux of the issue I'm trying to point out here. You can probably also "fix" this issue by passing a pointer-to-pointer to the kernel instead. You would then need to allocate for an array of pointers, and assign one of the individual pointers using the in-kernel new directly, as you have shown.
The remainder of your code has a great many items undefined. For example in the above code it's not clear why you would declare that production is a pointer to a DeviceProduction type, but then try to allocate an AProduction type to it. Presumably that is some form of object inheritance which is unclear.
Since you haven't really provided anything approaching a complete code, I've borrowed some pieces from here to put together a complete worked example, showing object creation/setup in one kernel, followed by another kernel that invokes virtual methods on those objects:
$ cat t1086.cu
#include <stdio.h>
#define N 4
class Polygon {
protected:
int width, height;
public:
__host__ __device__ void set_values (int a, int b)
{ width=a; height=b; }
__host__ __device__ virtual int area ()
{ return 0; }
};
class Rectangle: public Polygon {
public:
__host__ __device__ int area ()
{ return width * height; }
};
class Triangle: public Polygon {
public:
__host__ __device__ int area ()
{ return (width * height / 2); }
};
__global__ void setup_f(Polygon ** d_polys) {
int idx = threadIdx.x+blockDim.x*blockIdx.x;
if (idx < N) {
if (idx%2)
d_polys[idx] = new Rectangle();
else
d_polys[idx] = new Triangle();
d_polys[idx]->set_values(5,12);
}};
__global__ void area_f(Polygon ** d_polys) {
int idx = threadIdx.x+blockDim.x*blockIdx.x;
if (idx < N){
printf("area of object %d = %d\n", idx, d_polys[idx]->area());
}};
int main () {
Polygon **devPolys;
cudaMalloc(&devPolys,N*sizeof(Polygon *));
setup_f<<<1,N>>>(devPolys);
area_f<<<1,N>>>(devPolys);
cudaDeviceSynchronize();
}
$ nvcc -o t1086 t1086.cu
$ cuda-memcheck ./t1086
========= CUDA-MEMCHECK
area of object 0 = 30
area of object 1 = 60
area of object 2 = 30
area of object 3 = 60
========= ERROR SUMMARY: 0 errors
$
Robert's suggestion seems to made it work:
__global__ void createAProduction(DeviceProduction** production) {
int idx = threadIdx.x+blockDim.x*blockIdx.x;
if(idx == 0) {
production[0] = new AProduction();
}
}
Called like this:
DeviceProduction ** devAProduction = NULL;
cudaMalloc(&devAProduction, sizeof(AProduction *));
createAProduction<<<1, 1>>>(devAProduction);
gpuErrchk( cudaPeekAtLastError() );
gpuErrchk( cudaDeviceSynchronize() );
But if I want to keep single pointer structure for deviceProductions array would it be ok to do sth. like this?
deviceProductions["A"] = (DeviceProduction *) malloc(sizeof(AProduction *));
gpuErrchk(cudaMemcpy(deviceProductions["A"], devAProduction, sizeof(AProduction *), cudaMemcpyDeviceToHost));
My intention was to copy the pointer (address) to the host memory from the device memory. Am I doing it right?
This code runs successfully and MQStruct constructor initialized the values as well, I can see in ExecuteThread function but in TestFunction, I get the garbage values for MQStruct.
I am passing address of struct "&MQStructObj" to _beginthreadex for parameters and This is the problem I guess
struct MQStruct {
MQStruct()
{
pointer=NULL;
serviceName=NULL;
durability=0;
msgType=0;
msgHeader=0;
msgId=NULL;
payload=NULL;
payloadSize=0;
ttl=0;
priority=0;
}
void* pointer;
wchar_t *serviceName;
int durability;
int msgType;
int msgHeader;
wchar_t *msgId;
wchar_t *payload;
int payloadSize;
int ttl;
int priority;
};
int ExecuteThread() {
HANDLE heartBeatThread;
unsigned int hbThreadID;
int result = 0;
MQStruct MQStructObj;
MQStructObj.pointer=this;
heartBeatThread = (HANDLE)_beginthreadex(NULL, 0 , &TestFunction, &MQStructObj, 0/*CREATE_SUSPENDED*/, &hbThreadID);
if ( heartBeatThread == 0 )
{
result = -1;
LogEvent(DEBUG_LOG,0, "Fail to create thread");
}
CloseHandle(heartBeatThread);
return result;
}
You guessed correctly.
You're passing the address of a local variable to your thread-proc-startup, then leaving scope (and destroying the object in the process). References to this object in your thread proc are there-after undefined behavior.
Dynamically allocate one with new and let the thread proc delete it.
MQStructObj is declared on the stack so will go out of scope and potentially be overwritten as soon as ExecuteThread completes.
If you want to use a stack object here, you'll need to add some synchronisation to allow your new thread to copy from MQStructObj before ExecuteThread returns.
Alternatively, normally preferably, you could allocate MQStructObj dynamically and leave the new thread to clean it up at its leisure
MQStruct* MQStructObj = new MQStruct();
MQStructObj->pointer=this;
heartBeatThread = (HANDLE)_beginthreadex(NULL, 0 , &TestFunction, MQStructObj, 0, &hbThreadID);
if ( heartBeatThread == 0 ) { // error
delete MQStructObj;
result = -1;
}
// ownership of MQStructObj transferred to new thread
Platform : Windows 7
I'm developing a project for known text cipher attack in which;
Main process creates n child processes
Child processes decrypt an encrypted string, key subspace is partitioned according to number of child processes
Communication between child processes are by a static variable
for(int i = 0; i<info.totalNumberOfChildren; i++)
{
startChild( &info.childInfoList[i]);
//_beginthread(startChild, 0, &info.childInfoList[i]);
}
Above code works fine since:
First child starts execution, the key is set as a number such as 8 for testing purposes which is within the first child's partition, so first child finds the key, reports and sets true the killSwitch.
All the other children that are created are closed even before checking the first key as the killSwitch is true.
When I however do this :
for(int i = 0; i<info.totalNumberOfChildren; i++)
{
//startChild( &info.childInfoList[i]);
_beginthread(startChild, 0, &info.childInfoList[i]);
}
I get an access violation error. What could possibly be my source of error ?
Edit: I will try to share as relevant code as I can
startChild does the following:
void startChild( void* pParams)
{
ChildInfo *ci = (ChildInfo*)pParams;
// cout<<"buraya geldi"<<endl;
ChildProcess cp(*ci);
// write to log
cp.completeNextJob();
}
childInfo holds the following :
// header file
class ChildInfo
{
public:
ChildInfo();
ChildInfo(char * encrypted, char * original, static bool killSwitch, int totalNumOfChildren, int idNum, int orjLen);
void getNextJob();
bool keyIsFound();
Des des;
void printTest();
bool stopExecution;
bool allIsChecked;
char * encyptedString;
char * originalString;
int id;
int orjStrLen;
private:
int lastJobCompleted;
int totalNumberOfChildren;
int jobDistBits;
};
completeNextJob() does the following :
void ChildProcess::completeNextJob()
{
cout<<"Child Id : "<<info.id<<endl;
// cout<<"Trying : "<<info.encyptedString<<endl; // here I got an error
char * newtrial = info.encyptedString;
char * cand = info.des.Decrypt(newtrial); // here I also get an error if I comment out
/*
cout<<"Resultant : "<<cand<<endl;
cout<<"Comparing with : "<<info.originalString<<endl;
*/
bool match = true;
for(int i = 0; i<info.orjStrLen; i++)
{
if(!(cand[i] == info.originalString[i]))
match = false;
}
if(match)
{
cout<<"It has been acknowledged "<<endl;
info.stopExecution = true;
return;
}
else
{
if(!info.keyIsFound())
{
if(!info.allIsChecked)
{
info.getNextJob();
completeNextJob();
}
else
{
}
}
else
{
}
}
}
decrypt() method does the following :
char * Des::Decrypt(char *Text1)
{
int i,a1,j,nB,m,iB,k,K,B[8],n,t,d,round;
char *Text=new char[1000];
unsigned char ch;
strcpy(Text,Text1); // this is where I get the error
i=strlen(Text);
keygen();
int mc=0;
for(iB=0,nB=0,m=0;m<(strlen(Text)/8);m++) //Repeat for TextLenth/8 times.
{
for(iB=0,i=0;i<8;i++,nB++)
{
ch=Text[nB];
n=(int)ch;//(int)Text[nB];
for(K=7;n>=1;K--)
{
B[K]=n%2; //Converting 8-Bytes to 64-bit Binary Format
n/=2;
} for(;K>=0;K--) B[K]=0;
for(K=0;K<8;K++,iB++) total[iB]=B[K]; //Now `total' contains the 64-Bit binary format of 8-Bytes
}
IP(); //Performing initial permutation on `total[64]'
for(i=0;i<64;i++) total[i]=ip[i]; //Store values of ip[64] into total[64]
for(i=0;i<32;i++) left[i]=total[i]; // +--> left[32]
// total[64]--|
for(;i<64;i++) right[i-32]=total[i];// +--> right[32]
for(round=1;round<=16;round++)
{
Expansion(); //Performing expansion on `right[32]' to get `expansion[48]'
xor_oneD(round);
substitution();//Perform substitution on xor1[48] to get sub[32]
permutation(); //Performing Permutation on sub[32] to get p[32]
xor_two(); //Performing XOR operation on left[32],p[32] to get xor2[32]
for(i=0;i<32;i++) left[i]=right[i]; //Dumping right[32] into left[32]
for(i=0;i<32;i++) right[i]=xor2[i]; //Dumping xor2[32] into right[32]
} //rounds end here
for(i=0;i<32;i++) temp[i]=right[i]; // Dumping -->[ swap32bit ]
for(;i<64;i++) temp[i]=left[i-32]; // left[32],right[32] into temp[64]
inverse(); //Inversing the bits of temp[64] to get inv[8][8]
/* Obtaining the Cypher-Text into final[1000]*/
k=128; d=0;
for(i=0;i<8;i++)
{
for(j=0;j<8;j++)
{
d=d+inv[i][j]*k;
k=k/2;
}
final[mc++]=(char)d;
k=128; d=0;
}
} //for loop ends here
final[mc]='\0';
char *final1=new char[1000];
for(i=0,j=strlen(Text);i<strlen(Text);i++,j++)
final1[i]=final[j]; final1[i]='\0';
return(final);
}
Windows is trying to tell you why your program crashed. Please use a debugger to see what Windows is talking about. Location X is important: it should tell you whether your program is dereferencing NULL, overflowing a buffer, or doing something else. The call stack at the time of the crash is also very important.
Debugger is your best friend, try to use it and check step by step what could cause this access violation.
I think that info.encyptedString is not initialized correctly and pointing to not allocated memory, but I cant be sure because you didn't show this part of code.
And of course you must protect your shared resources (info) using some synchronization objects like critical section or mutex or semaphore.
I don't know, the basic issue seems pretty straightforward to me. You have multiple threads executing simultaneously, which access the same information via *pParams, which presumably is of type ChildInfo since that's what you cast it to. That info must be getting accessed elsewhere in the program, perhaps in the main thread. This is corrupting something, which may or may not have to do with Text1 or info.id, these errors can often be 'non-local' and hard to debug for this reason. So start mutex-protecting the entire thread (within your initial loop), and then zero in on the critical sections by trial and error, i.e. mutex-protect as small a region of code as you can get away with without producing errors.
I have a situation in Visual C++ 2008 that I have not seen before. I have a class with 4 STL objects (list and vector to be precise) and integers.
It has a method:
inline int id() { return m_id; }
The return value from this method is corrupt, and I have no idea why.
debugger screenshot http://img687.imageshack.us/img687/6728/returnvalue.png
I'd like to believe its a stack smash, but as far as I know, I have no buffer over-runs or allocation issues.
Some more observations
Here's something that puts me off. The debugger prints right values in the place mentioned // wrong ID.
m_header = new DnsHeader();
assert(_CrtCheckMemory());
if (m_header->init(bytes, size))
{
eprintf("0The header ID is %d\n", m_header->id()); // wrong ID!!!
inside m_header->init()
m_qdcount = ntohs(h->qdcount);
m_ancount = ntohs(h->ancount);
m_nscount = ntohs(h->nscount);
m_arcount = ntohs(h->arcount);
eprintf("The details are %d,%d,%d,%d\n", m_qdcount, m_ancount, m_nscount, m_arcount);
// copy the flags
// this doesn't work with a bitfield struct :(
// memcpy(&m_flags, bytes + 2, sizeof(m_flags));
//unpack_flags(bytes + 2); //TODO
m_init = true;
}
eprintf("Assigning an id of %d\n", m_id); // Correct ID.
return
m_header->id() is an inline function in the header file
inline int id() { return m_id; }
I don't really know how best to post the code snippets I have , but here's my best shot at it. Please do let me know if they are insufficient:
Class DnsHeader has an object m_header inside DnsPacket.
Main body:
DnsPacket *p ;
p = new DnsPacket(r);
assert (_CrtCheckMemory());
p->add_bytes(buf, r); // add bytes to a vector m_bytes inside DnsPacket
if (p->parse())
{
read_packet(sin, *p);
}
p->parse:
size_t size = m_bytes.size(); // m_bytes is a vector
unsigned char *bytes = new u_char[m_bytes.size()];
copy(m_bytes.begin(), m_bytes.end(), bytes);
m_header = new DnsHeader();
eprintf("m_header allocated at %x\n", m_header);
assert(_CrtCheckMemory());
if (m_header->init(bytes, size)) // just set the ID and a bunch of other ints here.
{
size_t pos = DnsHeader::SIZE; // const int
if (pos != size)
; // XXX perhaps generate a warning about extraneous data?
if (ok)
m_parsed = true;
}
else
{
m_parsed = false;
}
if (!ok) {
m_parsed = false;
}
return m_parsed;
}
read_packet:
DnsHeader& h = p.header();
eprintf("The header ID is %d\n", h.id()); // ID is wrong here
...
DnsHeader constructor:
m_id = -1;
m_qdcount = m_ancount = m_nscount = m_arcount = 0;
memset(&m_flags, 0, sizeof(m_flags)); // m_flags is a struct
m_flags.rd = 1;
p.header():
return *m_header;
m_header->init: (u_char* bytes, int size)
header_fmt *h = (header_fmt *)bytes;
m_id = ntohs(h->id);
eprintf("Assigning an id of %d/%d\n", ntohs(h->id), m_id); // ID is correct here
m_qdcount = ntohs(h->qdcount);
m_ancount = ntohs(h->ancount);
m_nscount = ntohs(h->nscount);
m_arcount = ntohs(h->arcount);
You seem to be using a pointer to an invalid class somehow. The return value shown is the value that VS usually uses to initialize memory with:
2^32 - 842150451 = 0xCDCDCDCD
You probably have not initialized the class that this function is a member of.
Without seeing more of the code in context.. it might be that the m_id is out of the scope you expect it to be in.
Reinstalled VC++. That fixed everything.
Thank you for your time and support everybody! :) Appreciate it!