User manual

MPLAB
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XC8 C Compiler User’s Guide
DS52053B-page 94  2012 Microchip Technology Inc.
4.8.2 -D: Define Macro
The -D option is used to define a preprocessor macro on the command line, exactly as
if it had been defined using a #define directive in the source code. This option may
take one of two forms, -Dmacro which is equivalent to:
#define macro 1
placed at the top of each module compiled using this option, or -Dmacro= text which
is equivalent to:
#define macro text
where text is the textual substitution required. Thus, the command:
xc8
--CHIP=16F877AA -Ddebug -Dbuffers=10 test.c
will compile test.c with macros defined exactly as if the C source code had included
the directives:
#define debug 1
#define buffers 10
Defining macros as C string literals requires bypassing any interpretation issues in the
operating system that is being used. To pass the C string, "hello world", (including
the quote characters) in the Windows environment, use: "-DMY_STRING=\\\"hello
world\\\"" (you must include the quote characters around the entire option as there
is a space character in the macro definition). Under Linux or Mac OS X, use:
-DMY_STRING=\"hello\ world\".
See Section 4.9 “MPLAB IDE V8 Universal Toolsuite Equivalents” or
Section 4.10 “MPLAB X Universal Toolsuite Equivalents” for use of this option in
MPLAB IDE.
4.8.3 -E: Redirect Compiler Errors to a File
This option has two purposes. The first is to change the format of displayed messages.
The second is to optionally allow messages to be directed to a file as some editors do
not allow the standard command line redirection facilities to be used when invoking the
compiler.
The general form of messages produced with the -E option in force is:
filename line_number: (message number) message string (type)
If a filename is specified immediately after -E, it is treated as the name of a file to which
all messages (errors, warnings, etc.) will be printed. For example, to compile x.c and
redirect all errors to x.err, use the command:
xc8
--CHIP=16F877AA -Ex.err x.c
The -E option also allows errors to be appended to an existing file by specifying an
addition character, +, at the start of the error filename, for example:
xc8
--CHIP=16F877AA -E+x.err y.c
If you wish to compile several files and combine all of the errors generated into a single
text file, use the -E option to create the file then use -E+ when compiling all the other
source files. For example, to compile a number of files with all errors combined into a
file called project.err, you could use the - E option as follows:
xc8
--CHIP=16F877AA -Eproject.err -O --PASS1 main.c
xc8 --CHIP=16F877AA -E+project.err -O --PASS1 part1.c
xc8 --CHIP=16F877AA -E+project.err -C asmcode.as
Section 4.6 “Compiler Messages” has more information regarding this option as well
as an overview of the messaging system and other related driver options.