Real- time software /fall 98

    The exercise is completed only if:

    • demonstrated to be working
    • a paper copy with cover sheet and listing is returned to the teacher (lab 4 and projects)
    Copying is strictly forbidden (see course rules).

    The exercises written with red letters are not mandatory to all (only to grades 4- 5).

    First we take some basic technologies as:

    • UNIX man- pages
    • compiling and linking a program using several separate source files
    • make- files
    • libraries, header files
    • procedure calling conventions
    • stack frame during program execution

    (1) Reading and understanding UNIX man-pages:

      Write a c- program which reads a name of a UNIX- system environment variable ( as "PATH" or "PS1".....) and outputs the value of this variable.

      Use the man page "getenv(3)" ( UNIX command line " man 3 getenv" )

      If for example Your UNIX- command prompt is ">" and You give the input "PS1" to Your program the output is ">".
       
       

    (2) Compiling/header files/linking/separate modules
     
      Write a c- program which reads a count of numbers, then integer numbers, finds the biggest of these and outputs the result. Seeking of the biggest must be in a separate module (a different source file). Use a header file.
       
            Libraries
     
      Read the manual page of the ar- command.
      Put the subprogram object file of the exercise (2) to your own library and test again.
      Study also dynamic libraries ( ld -b ..., dld.sl) make a simple documentation of Your experiment
       
       
       
    (3) Make- files
      (a) Read the manual page of make- command.
      (b) Do a makefile for the exercise (2). You have a makefile in which You use library and other without library.

      (c) Study Linux make- files. You can get the complete material of Linux configuration from the file or from Your own computer. Make an experiment of Your own with the following features:

        • make an as simple example program set as possible for experiment
        • include- command in make- file
        • make -C dir
        • use ".c.o:" style rule
        • linking sets of objects to an object and then these objects to an executable

         
         
       
    (4) Modify a simple IPC- example from course material (6.1.1).
     
      We replace reading two numbers by reading a name, adding two numbers by seeking a telephone number from a file (based on the name) and printing the sum by printing the phone number.

      We got a phone number client/server- example. Client is asking a phone number from server.
       
       
       

           
    Use GNU debugger gdb to test a program
        • Compile "gcc -g  -static file.c -o file_exe"
        • Start debugger "gdb file_exe"
        • Example commands (see manual for further details):
            • help
            • help brekpoints
            • break subroutine_XXXX
            • data YYYYY
            • run
            • step
            • step
            • ...........
            • disassemble subroutine_XXXX
            • bt

              • ......