HP 3000 Manuals

Getting Started as an MPE/iX Programmer Programmer's Guide

Creating an Executable Program File 

HP Link Editor/XL creates executable program files from relocatable
object files and relocatable libraries in the following way.  First, it
merges selected relocatable object files and libraries into one module
and resolves inter-module references.  Then, it searches selected
relocatable libraries, resolving external references to symbols undefined
after the merge operation.  When a relocatable object module in the
library resolves an external reference, the module is merged into the
executable program file that is being built.  In the last step, HP Link
Editor/XL assigns virtual addresses to all symbols, binds references to
the known symbols within each relocatable object module, and puts the
resulting executable program in a form that the loader can process.
Figure 4-3  shows the files HP Link Editor/XL uses when it creates an
executable program file.


          Figure 4-3.  Creating an Executable Program File 

An executable program file contains only one program entry point, which
marks the instruction where execution begins.  Each language defines its
own program entry point.  For example, HP FORTRAN 77/iX uses the main
program as the entry point, while HP Pascal/iX uses a program's outer
block as the entry point.  When creating an executable program file, HP
Link Editor/XL separates code and data areas, as shown in Figure 4-4 .

The functions of the LINK command are:

   *   Binding
   *   Merging relocatable object modules
   *   Searching relocatable libraries (RLs)


          Figure 4-4.  Linking to Create an Executable Program File 

Figure 4-5  shows HP Link Editor/XL executable program file commands
along with the files that they use.


          Figure 4-5.  Executable Program File Commands 

MPE/iX 5.0 Documentation