CCS C Software and Maintenance Offers
FAQFAQ   FAQForum Help   FAQOfficial CCS Support   SearchSearch  RegisterRegister 

ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

CCS does not monitor this forum on a regular basis.

Please do not post bug reports on this forum. Send them to support@ccsinfo.com

stricmp()

 
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion
View previous topic :: View next topic  
Author Message
eugeneb
Guest







stricmp()
PostPosted: Thu May 29, 2003 10:13 am     Reply with quote

If I can do this:
if (strcpy(w_cmd, "wexit"))

Why can't I do this?
if (!stricmp(w_cmd, "wexit"))
// Results in bad experession syntax on "wexit"

I am using get_string(...) to capture a 6 byte string. I then need to compare the string to available commands.
pseudo... if (w_cmd==some_cmd) then...

I can do this:
char wexit[6]="wexit";
...
if (!stricmp(w_cmd, wexit))...

but this method could tie up 100's of bytes of RAM.

I am using CCS PCH v3.158 for a 18F6720.


___________________________
This message was ported from CCS's old forum
Original Post ID: 144514852
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

View user's profile Send private message

Re: stricmp()
PostPosted: Thu May 29, 2003 11:23 am     Reply with quote

:=If I can do this:
:= if (strcpy(w_cmd, "wexit"))
:=
:=Why can't I do this?
:= if (!stricmp(w_cmd, "wexit"))
:= // Results in bad experession syntax on "wexit"

This would be the same old CCS limitation of "no pointers
to constant strings". Here's the function stricmp from
the string.h file:

signed int stricmp(char *s1, char *s2)

It's expecting pointers to the strings. But, you can't pass
a pointer to a constant string in CCS. You have to copy it
to ram first, with strcpy.

:=
:=I am using get_string(...) to capture a 6 byte string. I then need to compare the string to available commands.
:= pseudo... if (w_cmd==some_cmd) then...
:=
:=I can do this:
:= char wexit[6]="wexit";
:= ...
:= if (!stricmp(w_cmd, wexit))...
:=
:= but this method could tie up 100's of bytes of RAM.
:=
:=I am using CCS PCH v3.158 for a 18F6720.
:=
:=
___________________________
This message was ported from CCS's old forum
Original Post ID: 144514856
eugeneb
Guest







Re: stricmp()
PostPosted: Thu May 29, 2003 3:52 pm     Reply with quote

The following is a solution received from CCS Support:

Because the PIC has separate RAM and ROM address spaces and the opcodes can not access the ROM space. The following is a better explination:

For data there is no way to know if a pointer is to RAM or to ROM becuase of the dual address space in the PIC and the inability to access ROM in most PICs. For example STRCMP could not know if the pointer being passed to it were RAM or ROM. You can pass an index into a constant array instead of the pointer however. For example:

char const keywords[21] = {"UP DOWN LEFT RIGHT"};

You can do:
int compare(char * cmd, byte index) {
int i;
for(i=0;i<5;i++,cmd++)
if(*cmd!=keywords[index+i])
return(FALSE);
return(TRUE);
}

int find_match(char * cmd) {
int i;
for(i=0;i<4;i++)
if(compare(cmd,i*5))
return(i+1);
return(0);
}


___________________________
This message was ported from CCS's old forum
Original Post ID: 144514870
Display posts from previous:   
Post new topic   Reply to topic    CCS Forum Index -> General CCS C Discussion All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group