Thank you so much shansen!
I just took “double* p = (double*)malloc(10*sizeof(double))” as an example to demonstrate I could not use function malloc,actually I wrote a small matrix library for specific calculation in which I need frequently allocate memory.However,thanks to your explanation and your advice,I decide to define array on the stack to store the value for matrix operation.In this way I can avoid dynamic
memory allocation,for I don't kwon much about linux.
Thank you again shansen!