Problem in using Pointer functions in C18 compiler - Electronic Circuits Projects Diagrams Free

Jyothi@Pic · 4th February 2009, 07:10 AM

Hi,

I have attached my code for correction since i am getting warning as

Warning [2054] suspicious pointer conversion

[CODE]
#include"string.h" // is included

void main()
{

printlcd1(" Hello world ");

}

void printlcd1(unsigned char *str)
{
unsigned char len,i;//RCIE=0;
len = strlen(str);
set_add(0x80); //sets display position in the first line
for(i=0;i<len;i++)
{
data_lcd(*str); //displays the character on LCD
str++;
}
//return;
}[CODE]

Above is the code when i build i am getting warning as

Warning [2054] suspicious pointer conversion

wat corrections is to be made
kindly reply for this

Pommie · 4th February 2009, 08:29 AM

There are two kinds of pointers on a Pic chip. One to ram and one to rom. Your function is defaulting to a ram pointer and the constant data "Hello World" is in rom.

There are two ways to fix this. First make them both rom pointers,

Code:

printlcd1((rom unsigned char*)" Hello world ");

void printlcd1(rom unsigned char *str)

The other way is to make them both ram pointers but the compiler will still store the constant string data in rom. You then have to copy the rom image to a ram buffer and point your function at the buffer.

Note that strlen expects a ram pointer so you would be better doing something like,

Code:

    while(*str){
        data_lcd(*str); //displays the character on LCD
        str++;
    }

Mike.

Jyothi@Pic · 4th February 2009, 08:56 AM

Thanks it worked

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4th February 2009, 07:10 AM	#1
Jyothi@Pic	Problem in using Pointer functions in C18 compiler Hi, I have attached my code for correction since i am getting warning as Warning [2054] suspicious pointer conversion [CODE] #include"string.h" // is included void main() { printlcd1(" Hello world "); } void printlcd1(unsigned char str) { unsigned char len,i;//RCIE=0; len = strlen(str); set_add(0x80); //sets display position in the first line for(i=0;i<len;i++) { data_lcd(str); //displays the character on LCD str++; } //return; }[CODE] Above is the code when i build i am getting warning as Warning [2054] suspicious pointer conversion wat corrections is to be made kindly reply for this

4th February 2009, 08:29 AM	#2
Pommie	There are two kinds of pointers on a Pic chip. One to ram and one to rom. Your function is defaulting to a ram pointer and the constant data "Hello World" is in rom. There are two ways to fix this. First make them both rom pointers, Code: printlcd1((rom unsigned char)" Hello world "); void printlcd1(rom unsigned char str) The other way is to make them both ram pointers but the compiler will still store the constant string data in rom. You then have to copy the rom image to a ram buffer and point your function at the buffer. Note that strlen expects a ram pointer so you would be better doing something like, Code: while(str){ data_lcd(str); //displays the character on LCD str++; } Mike.