C/C++ • Re: Pico SDK compilation question re placement of preprocessor directives

1. When you say "subroutine", could that be a function; e.g. 'void preproc (void) { }') ??

I tend to call a function with void return a "subroutine". Old Fortran habit.

2. Isn't it true that someone made a choice to include these "fn calls, preprocessor macros, etc" under a preprocessor directive? I mean, there must be another way to do this - is that not true?

I am not quite clear what you mean by "under a preprocessor directive". If you are referring to the use of #if !defined..., then yes somebody has made the decision to have a run-time error message rather than compile-time. It could perhaps be written something like:

Code:

#if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)#error i2c/bus_scan example requires a board with I2C pins#endifvoid main (void)   {    // This example will use I2C0 on the default SDA and SCL pins (GP4, GP5 on a Pico)    i2c_init(i2c_default, 100 * 1000);    gpio_set_function(PICO_DEFAULT_I2C_SDA_PIN, GPIO_FUNC_I2C);    gpio_set_function(PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C);    gpio_pull_up(PICO_DEFAULT_I2C_SDA_PIN);    gpio_pull_up(PICO_DEFAULT_I2C_SCL_PIN);    // Make the I2C pins available to picotool    bi_decl(bi_2pins_with_func(PICO_DEFAULT_I2C_SDA_PIN, PICO_DEFAULT_I2C_SCL_PIN, GPIO_FUNC_I2C));

This version will fail to compile if the required macros are not defined. I tend to prefer this version. Not much point in creating an executable if it is known that it will not run.

Statistics: Posted by irishmonk-57 — Wed Jan 31, 2024 8:46 am