Hi! I have to make a simple system call to minix, but I'm new in Minix... I tried to follow the steps from a document, but when I compile ("make install" - of what I read, it's something like a compiler :-?? ) I have an error : undefined _do_getpids. And I don't understand why, cause I followed the steps from this pdf : http://www-di.inf.puc-rio.br/~endler...M-sys-call.pdf. In fact, first I had an error to m_in.endpt (at step 5 ) - that m_in.endpt is undefined..so, I declared endpoint_t endpt; endpt=m_in.REP_ENDPT. I don't if this is good, too.. My task is:

A Simple System Call.
In the second week each team writes a simple system call to fetch from the memory manager (MM) the running
processí process id (PID) and its parentís PID, and writes a user-level program to test the system call. The
prototype, from the man page, is:
#include // The team-supplied header file
int GetPIDs (pid_t *Me, pid_t *Mom);
To implement this simple system call, the students must: (1) modify one system header file, minix/callnr.h, (2)
add the header file prog2.h to /usr/include, (3) add their source code to /usr/src/lib/other, (4) put their
object files in /usr/lib/i386/libs.a, (5) modify /usr/src/mm/{proto.h,table.c,Makefile}, and (6)
add a source-code file to /usr/src/mm.
Their test programs must fork a binary tree of processes at least four deep. The teams are told to use
getpid(2) and getppid(2) to validate their results.
The students find with this assignment that they write relatively little code, but the code that they do write, as
shown above, is scattered throughout Minix. They quickly discover the benefits of advanced planning, careful code
reading, and grep(1) and find(1).

Please, could you help me?.. Thank you very much..