Re: What does "error: expected expression before '/' token" really mean?

On Wed, Jul 23, 2014 at 03:22:06PM -0400, Bob Paddock wrote:
>  Can someone tell me please what this error really means?:
> 
> "error: expected expression before '/' token"
> 
> Googling says it is from using C++ style comments, in C code, which is
> not the case here.
> 
> I can find no place where there actually *is* a '/' token in relation
> to the error:
> 
> avr-gcc (AVR_8_bit_GNU_Toolchain_3.4.4_1229) 4.8.1
> 
>  [GCC]     : Compiling C File: "Version/version.c" to
> "[../Firmware_Project/Project/Object/]
> ../Firmware_Project/Project/Object/Version/version.o"
> 
> J:\APPS/AVR_TC_344_1229/bin/avr-gcc [see command line below]
> <command-line>:0:11: error: expected expression before '/' token
> 
> Version/version.c:25:48: note: in expansion of macro 'MODEL_STR'
>  const char Model_Prj_str[]      VERSION_INFO = MODEL_STR;
> /* Model */
>                                                 ^
> This is how MODEL_STR has been defined for a very long time (changed
> the project name for posting here):
> 
> -DMODEL_STR=\"Project\"
> 
> This has something to do with the build system and not the actual
> source code, as the build system is what was recently changed.
> The error goes away if I take the multiplication out of this line:
> 
> CDEFS += -DALARM_SET_POINT_MAX=(15U*60U)
> 
> so it just reads as :
> 
> CDEFS += -DALARM_SET_POINT_MAX=15
> 
> That definition is not used, nor even included in anyway outside of
> the command line, in the file that is complaining about the '/' token.
> 
> I can invoke the same error by adding parentheses around this line:
> 
> CDEFS += -DSCRN_Y_BYTES=$(SCRN_HEIGHT)/8U
> 
> to yield:
> 
> CDEFS += -DSCRN_Y_BYTES=($(SCRN_HEIGHT)/8U)
> 
> This is the compile command line, split on spaces due to its length to show it
> here, normally it would be one LONG line:
> J:\APPS/AVR_TC_344_1229/bin/avr-gcc
> -c
> -mmcu=atxmega128a1
> -DSCRN_HEIGHT=32U
> -DSCRN_LENGTH=120U
> -DSCRN_LEFT=0U
> -DSCRN_TOP=0U
> -DSCRN_RIGHT=120U-1U
> -DSCRN_BOTTOM=32U-1U
> -DSCRN_X_BYTES=120U
> -DSCRN_Y_BYTES=32U/8U
> -DMODEL_NAME_TEXT=\"CompanyName\"
> -DLOGO_MODEL_NAME=\"Name\"
> -DLOGO_WIDTH=120U
> -DLOGO_HIGHT=21U
> -DLOGO_TEXT_POSITION_X=SCRN_LEFT+1U
> -DLOGO_TEXT_POSITION_Y=SCRN_TOP+20U
> -DLOGO_TEXT_FONT_SIZE=FONT_DINA_SIX_DOT
> -DPCB_REV_A=1U
> -DALARM_SET_POINT_MAX=15*1
> -DMODEL_STR=\"Project\"
> -DFIRMWARE_NUMBER=0U
> -DFIRMWARE_REV_STR=\"v0.0.0\"
> -DFIRMWARE_REV_NUMBER_STR=\"000\"
> -DBACKLIGHT_BUTTON_TIME=10U
> [Many other -D's snipped]
> -IVersion/
> [Many other -I's snipped]
> -I.
> -g
> -Os
> -funsigned-char
> -funsigned-bitfields
> -std=gnu99
> -Wa,-adhlns=../Firmware_Project/Project/Object/Version/version.lst
> -DF_CPU=4000000UL
> -Datxmega128a1
> -DNEW_BUILDNUMBER=911
> -DNEW_BUILDNUMBER_TEXT=\"911\"
> -MMD
> -MP
> -MF ../Firmware_Project/Project/Dep/version.o.d
> Version/version.c
> -o ../Firmware_Project/Project/Object/Version/version.o

Perhaps the shell is kicking in and transforming the arithmetic
expression in some way before it is passed to the compiler? Does
wrappping the expression or the -D option itself in single quotes help?
> 
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