Intel XENIX 286 Programmers Guide (86) - Tenox.tc

cc: C Compiler XENIX Programming
The command compiles the statements in main.c, then compiles the statements in add.c.
Finally, it links the two together (along with the standard C library) and copies the
program to a.out. This program, like the program in the previous section, waits for two
numbers, then prints their sum.
Since the cc command cannot keep track of more than one compiled file at a time, when
several source files are compiled at a time, the command creates object files to hold
the binary code generated for each source file. These object files are then linked to
create an executable program. The object files have the same base name as the source
files but are given the ".o" file extension. For example, when you compile the two
source files above, the compiler produces the object files main.o and add.o. These files
are permanent files, i.e., the command does not delete them after completing its
operation. Note that the command also creates an object file if only one source file is
compiled.
Naming the Output File
You can give the executable program file any valid file name by using the -o (for
"output") option. The option has the form
-o filename
where filename is a valid file name or path name. If a file name is given, the program
file is stored in the current directory. If a full path name is given, the file is stored in
the given directory. If that file already exists, its contents are replaced with the new
executable program.
For example, the command
cc -o addem main.c add.o
causes the compiler to create an executable program file addem from the source file
main.c and object file add.o. You can execute this program by typing
add em
Note that the -o option does not affect the existing a.out file. This means that the cc
command does not change the current contents of a.out if the -o option has been given.
Compiling Programs for the MS-DOS Environment
The XENIX C compiler can compile programs that will operate in either the MS-DOS or
the XENIX environment. However, to compile a program for the MS-DOS environment,
you must use a different set of standard libraries and a different linker.
The -dos option instructs the compiler to alter the standard search path and to search
the appropriate libraries for the MS-DOS environment. Note that programs compiled
with these libraries will not run in the XENIX environment.
2-4