Real-time programming introductory exercises (year 97-98)

The following programs are only few lines of c- code. The first gives You an idea how the UNIX- system call interface is documented. The second exercise teach to You how to combine several source codes in a working program and how to use UNIX- libraries. You can use GNU or HP c- compliler.

(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/make- command/archives- in the UNIX environment:

• See the man pages of :
  
• cc
• ld
• ar ( this command tells how to put modules to a program library)
• make (this command makes it possible to compile only changed parts of Your program and tells to the compier how to build up a program from different source files)





• Write a c- program which reads two integer numbers, adds them and outputs the result.
• Adding in the SEPARATE MODULE (file "add.c" )
• The prototype of adding in the file "add.h"
• Write a "make file"" for the program
• Compile the c- program
  
• Make the library ""mylib.a"", store "add.o"" to this library, compile the program
  using the library