B
, K
, M
or G
, in which
case the size is, respectively, in bytes, kilobytes, megabytes
or gigabytes. This is different from pthread_attr_setstacksize
which gets the number of bytes as an argument. If the stacksize cannot
be set due to system constraints, an error is reported and the initial
stacksize is left unchanged. If undefined, the stack size is system
dependent.