RE: [avr-gcc-list] Adding date/version information to project??

[Matt.VanDeWerken]

I tried exactly this, however I now get a linker error:

c:\apps\WinAVR\bin\..\lib\gcc\avr\3.4.3\..\..\..\..\avr\bin\ld.exe:main.
o: file format not recognized; treating as linker script
c:\apps\WinAVR\bin\..\lib\gcc\avr\3.4.3\..\..\..\..\avr\bin\ld.exe:main.
o:1: parse error
make: *** [main.elf] Error 1

I change the makefile back (ie, removing the reference to buildtime) and
it compiles again.

Any ideas on this one??

The relevent section in my makefile is:

=====8><----------------------------------------------------------------
-
# Link: create ELF output file from object files.
.SECONDARY : $(TARGET).elf
.PRECIOUS : $(OBJ)
%.elf: $(OBJ)
        @echo
        @echo $(MSG_LINKING) $@
        $(CC) -c $(ALL_CFLAGS) buildtime.c --output buildtime.o 
        $(CC) $(ALL_CFLAGS) $(OBJ) buildtime.o --output $@ $(LDFLAGS)

=====8><----------------------------------------------------------------
-

To make it work, I change the last two lines above back to this line:
        $(CC) $(ALL_CFLAGS) $(OBJ) --output $@ $(LDFLAGS)

I have no idea why it doesn't work; the contents of buildtime.c is as
follows:

=====8><----------------------------------------------------------------
-

#include <avr/pgmspace.h>
#include "buildtime.h"

const char BUILDTIME[] PROGMEM = (__DATE__ " " __TIME__);

=====8><----------------------------------------------------------------
-

Buildtime.h is as follows:
=====8><----------------------------------------------------------------
-

#ifndef __BUILDTIME_H
#define __BUILDTIME_H

#include <avr/pgmspace.h>

extern const char BUILDTIME[] PROGMEM;

#endif

=====8><----------------------------------------------------------------
-

I'm at a total loss as to why it will work without the file being linked
but not with.

Cheers,
Matthew van de Werken - Electronics Engineer
CSIRO E&M - Rock Mass Characterisation - 1 Technology Court - Pullenvale
- 4069
p: (07) 3327 4142 * f: (07) 3327 4455 * e: address@hidden
"We do not inherit the earth from our ancestors, we borrow it from our
children." 
-- Native American Proverb

> -----Original Message-----
> From: 
> address@hidden 
> [mailto:address@hidden
> org] On Behalf Of Bruce D. Lightner
> Sent: Wednesday, 30 November 2005 8:23 AM
> To: address@hidden
> Subject: Re: [avr-gcc-list] Adding date/version information 
> to project??
> 
> 
> address@hidden wrote:
> > Hi all:
> > 
> > I am looking for an automated way to update a static string 
> in program 
> > space when my project is built. Is there an easy way to do this, 
> > either by adding an extra target to the makefile, or some 
> other way? 
> > I'd prefer not to manually have to change the information, and I'd 
> > also prefer for it to NOT change when none of the other 
> source files 
> > change. That is, the requirement is as follows:
> > 
> > 1. The date/other information is changed when a build occurs, ie 
> > "make" or "make all" or "make target" - basically anything 
> which calls 
> > the linker; maybe the clue is there. 2. The date/other info is NOT 
> > changed when a build does not occur. Eg, "make program" causes no 
> > change in the string if the linker is not called, nor does 
> it change 
> > if the target is up to date already. 3. I know all this can be done 
> > using CVS/SVN $Id$ tags, but I don't have a cvs/svn server here at 
> > work, and I don't want to go through the hassle of setting 
> one up in 
> > this windows-only shop. I also know that I should be using version 
> > control here...
> > 
> > Any ideas??
> 
> I *too* like having a "build time" timestamp string somewhere 
> in my executable programs.  It seems to me that this is 
> especially important for embedded firmware.
> 
> One way to do this is to add "Makefile" logic to force the 
> update of a timestamp string in a separate source file 
> whenever the project is re-linked.  One can force this 
> "update" by unconditionally re-compiling a source code module 
> containing an automatically updating timestamp string just 
> before the "link" step in the "Makefile".  The built-in C 
> macros __DATE__ and __TIME__ make this straightforward.
> 
> Here's what I usually do...
> 
> (1) Create a separate compilation module with a date/time string (two
> files: "version.c" and "version.h")...
> 
>       // version.h
>       extern const char build_time[];
> 
>       // version.c
>       #include "version.h"
>       const char build_time[] = __DATE__" "__TIME__;
> 
> In the case of "avr-gcc", you'll probably want to add 
> "PROGMEM" after "build_time[]" in both of the above source 
> files to force the string into program memory instead of SRAM.
> 
> (2) Reference the "build_time" string as required in your 
> other project source file(s) by using the include file 
> "version.h".  The string will end up containing something like this...
> 
>       "Nov 29 2005 17:01:41"
> 
> (3) Add logic to your "Makefile" just before the "link" 
> command to unconditionally re-compile "version.c".  Also, be 
> sure to include "version.o" in the list of object files being linked.
> 
> For example:
> 
>    %.elf: $(OBJ)
>             @echo $(MSG_LINKING) $@
>             $(CC) $(ALL_CFLAGS) version.c --output version.o
>             $(CC) $(ALL_CFLAGS) $^ version.o --output $@ $(LDFLAGS)
> 
> Note that you don't absolutely have to include "version.o" in 
> the $(OBJ) list.  If you do, then remove the reference to 
> "version.o" from the above "link" $(CC) command.
> 
> Anyway, this "make" logic causes the "build_time" string to be updated
> *only* when the program is actually linked.
> 
> Best regards,
> 
> Bruce
> 
> -- 
>   Bruce D. Lightner
>   Lightner Engineering
>   La Jolla, California
>   Voice: +1-858-551-4011
>   FAX: +1-858-551-0777
>   Email: address@hidden
>   URL: http://www.lightner.net/lightner/bruce/
> 
> 
> 
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