Hi, The Stack of task grow from high memory to low memory. prvTaskCheckFreeStackSpace{} get as an argument a pointer of start of the stack ( The address got from pvPortMalloc). This address is the low address of the stack and it is static at the all run time of the system. Why the pointer is decremented and not incremented in the function prvTaskCheckFreeStackSpace ?

The line I think you are seeing is:

        pucStackByte -= portSTACK_GROWTH;

Note, the direction the stack grows is processor dependent, and portSTACK_GROWTH is a define with a value of 1 if the line grows low to high and -1 if it grows high to low, so in that case we subtract -1, which is effectively an increment.

Ok Richard. Thank you very much !