Small Device C Compiler suite

Hello all,
    I am trying to use sdcc for 8051. I am facing problems=20
with structures and pointers.There are a lot of compiling errors
and most often errors are visible only while debugging.
    My request is are there any guidelines, restrictions=20
imposed like "no pointer arthmetic allowed" or "all members=20
in a structure should be named and referred to by name" etc..
    I have come across such restrictions with Tasking compilers.
Can somebody enlighten me,
Thank you,
varadaraju