MPLAB XC8 Warning meaning ??

[Mamdouh1]

Hi everybody .
what is this warning meaning in MPLAB XC8 and how avoid it ??

newmain.c:63: warning: (359) illegal conversion between pointer types

The code cause this warning come from :

   LCD_Out_Cp(">>>");

the function is :

---

Code C - [expand]
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void LCD_Out_Cp(unsigned char *Str)
    {
         while(*Str)
                  LCD_Chr_Cp(*Str++);
     }

---

thanks for help .

 

[qwertyuiop415263]

you are assigning address of a constant string to non constant char pointer. That is why compiler gave this warning. Use below code to avoid this warning

#pragma warning disable 359

 

[Mamdouh1]

Thanks for reply ,
I get another warning from this line :

 LCD_Out("Sec L",2,3);

newmain.c:43: warning: (359) illegal conversion between pointer types
pointer to const unsigned char -> pointer to unsigned char

the function is :

---

Code C - [expand]
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void LCD_Out_Cp(unsigned char  *Str)
{
    while(*Str)
        LCD_Chr_Cp(*Str++);
}
 
void LCD_Out(unsigned char *Str1,unsigned char raw,unsigned char column)
{
    if(raw==1)
    {
       LCD_Cmd(0x80+column);
       LCD_Out_Cp(*Str1);
    }
    if(raw==2)
    {
        LCD_Cmd(0xC0+column);
        LCD_Out_Cp(*Str1);
    }
}

---

 

[imran_199127]

For all string transmissions if you have const char* input i.e. input like "Hello World" instead of pointer use pointer type cast to resolve the issue, for e.g.

LCD_Out_Cp((unsigned char*)"Hello World!");

I see that your Line 17 is wrong, you need to pass a pointer to LCD_Out_Cp and hence only Str1 not *Str. You are using *Str in your LCD_Out_Cp function which means that Str is an address, so use Str not *Str and if you get warnings or errors about pointer type conversions then use type casting for pointers.

Also, use this instead

LCD_Out((unsigned char*)"Sec L", 2, 3);

 

[Mamdouh1]

Thank you very much.

 

[Surender Reddy]

For pointer concept
*str returns value, str returns address of the value.
So allways keep in mind that print the value and increase the address and print the value and so on....

XC8 compiler creates errors for pointers, but C18 compiler does'nt.

Thanks for reply ,
I get another warning from this line :

 LCD_Out("Sec L",2,3);

the function is :

---

Code C - [expand]
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void LCD_Out_Cp(unsigned char  *Str)
{
    while(*Str)
        LCD_Chr_Cp(*Str++);
}
 
void LCD_Out(unsigned char *Str1,unsigned char raw,unsigned char column)
{
    if(raw==1)
    {
       LCD_Cmd(0x80+column);
       LCD_Out_Cp(*Str1);
    }
    if(raw==2)
    {
        LCD_Cmd(0xC0+column);
        LCD_Out_Cp(*Str1);
    }
}

---