Calls to sbrk(II) appear to have a delayed effect in our Berkeley VAX 4.1 system. main() { printf( "sbrk(0) = %x\n", sbrk(0) ); printf( "sbrk(1) = %x\n", sbrk(1) ); printf( "sbrk(0) = %x\n", sbrk(0) ); } produces the following output: sbrk(0) = 19c4 sbrk(1) = 19c4 sbrk(0) = 19c5