当我使用pin_ptr在本机c代码中传递数组时,我会遇到访问冲突。代码如下:
array<float>^ LogLikelihoodScore(array<array<unsigned char>^>^ modelsBuffer , array<float>^ featuresArray, int numberOfFrames)
{
int i, j, modelsNum = modelsBuffer->Length, len;
float **models = (float**) malloc(modelsNum * sizeof(void*));
for(i = 0; i < modelsNum; i++)
{
pin_ptr<unsigned char> ptr = &modelsBuffer[i][0];
models[i] = (float*) ptr;
}
array<float>^ scores = gcnew array<float>(modelsNum);
pin_ptr<float> scoresPtr = &scores[0];
pin_ptr<float> featuresPtr = &featuresArray[0];
char* message = CalculateLikelihoodUsingBufferedModels(models, modelsNum, featuresPtr, numberOfFrames, scoresPtr);
return scores;
}
当我更改此代码以便分配新空格并将原始数组复制到该代码时,我没有获得访问冲突。 新代码:
array<float>^ LogLikelihoodScore(array<array<unsigned char>^>^ modelsBuffer , array<float>^ featuresArray, int numberOfFrames)
{
int i, j, modelsNum = modelsBuffer->Length, len;
float **models = (float**) malloc(modelsNum * sizeof(void*));
for(i = 0; i < modelsNum; i++)
{
len = modelsBuffer[i]->Length;
char* ptr = (char*) malloc(len);
pin_ptr<unsigned char> ptr2 = &modelsBuffer[i][0];
memcpy(ptr, ptr2, len);
models[i] = (float*) ptr;
}
array<float>^ scores = gcnew array<float>(modelsNum);
pin_ptr<float> scoresPtr = &scores[0];
pin_ptr<float> featuresPtr = &featuresArray[0];
char* message = CalculateLikelihoodUsingBufferedModels(models, modelsNum, featuresPtr, numberOfFrames, scoresPtr);
return scores;
}
问题:我在使用pin_ptr时遇到任何问题吗?
答案 0 :(得分:3)
当钉扎指针超出范围时,该对象不再被视为固定,除非有其他钉扎指针指向或进入对象。您不必明确取消指针。
正如the docs所述,pin_ptr
仅在目标处于范围时将其定位。这意味着在下一个循环的每次迭代之后,取消固定对象,使得存储的指针无用。
for(i = 0; i < modelsNum; i++)
{
pin_ptr<unsigned char> ptr = &modelsBuffer[i][0];
models[i] = (float*) ptr;
}