From: Manu Abraham <abraham.manu@gmail.com>
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Date: Thu, 30 Jul 2020 09:55:15 -0700
Subject: Re: [PIC] Simple GCC question
Thread-Topic: [PIC] Simple GCC question
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On Thu, Jul 30, 2020 at 9:57 PM Bob Blick <bobblick@outlook.com> wrote:
>
> I'm using a nice little HD44780 LCD library in an STM32 project, it works=
 great but I'm stuck with a variable scope problem that I can only seem to =
make worse because GCC is a bit stricter than I want it to be at this point=
.. Sorry if the code example doesn't wordwrap properly.
>
> If, somewhere in main() I create an instance of the LCD like this:
>   Lcd_PortType ports[] =3D {LCD_D4_GPIO_Port, LCD_D5_GPIO_Port, LCD_D6_GP=
IO_Port, LCD_D7_GPIO_Port};
>   Lcd_PinType pins[] =3D {LCD_D4_Pin, LCD_D5_Pin, LCD_D6_Pin, LCD_D7_Pin}=
;
>   Lcd_HandleTypeDef lcd =3D Lcd_create(ports, pins, LCD_RS_GPIO_Port, LCD=
_RS_Pin, LCD_EN_GPIO_Port, LCD_EN_Pin, LCD_4_BIT_MODE);
>

Why I dislike opaque datatypes...

Instead of copying objects to Lcd_create(), a pointer could have been used,
storage could have been global, made static ..
the variables appear to be for configuration purposes ?

One way to do is make the lcd object global.

Another way is to pass a lcd object pointer to whatever function you
are calling,
unless you need to access the lcd object from interrupt context.
If you need access from interrupt context, the easier way is to have
global storage.

--=20
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