can #undef, #define used in subroutine for memory addressing

[simon630]

Hi, friends,
I am wondering whether these two pre-processor directives could be used in subroutine.
here is a sample programme.

#define SERIAL_NO 5
.
.
.
void routine1(){
if (a>5)
#undef SERIAL_NO
#define SERIAL_NO 10
}

void write_ram(){
//SERIAL_NO is used as the address of memory access
}

main(){

}
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This message was ported from CCS's old forum
Original Post ID: 144515735

[neil]

<font face="Courier New" size=-1>Hello, I'm not absolutely sure, but I think #define and #undef are just compiler directives which are evaluated by the compiler, not the PIC. If you try to use compiler directives at run time, I would expect the compiler to give an error.

If you want to store a nonvolatile serial number on a chip, but want to be able to change it, why not use a device with internal E²PROM such as 16Fxxx and put the serial no. in E²

Regards,
Neil.

:=Hi, friends,
:= I am wondering whether these two pre-processor directives could be used in subroutine.
:= here is a sample programme.
:=
:=#define SERIAL_NO 5
:=.
:=.
:=.
:=void routine1(){
:=if (a>5)
:=#undef SERIAL_NO
:=#define SERIAL_NO 10
:=}
:=
:=void write_ram(){
:= //SERIAL_NO is used as the address of memory access
:=}
:=
:=main(){
:=
:=}</font>
___________________________
This message was ported from CCS's old forum
Original Post ID: 144515738