Stacksize Freemem obtain stack reservation size stacksize freemem For a description of the meaning and use of this call, the user is referred to the Memory Management section of this manual. If the stack check code is in effect, a call to stacksize will return the maximum number of bytes of stack used at the time of the call. This call can be used to determine the stack size required by a program. Freemem() will return the number of bytes of the stack that has not been used. ibrk(), sbrk(), Global variable "memend" and value "end".