robitabu:
Why should I even bother with calling assert() then?
Welcome to "Design by Contract" ... Design by contract - Wikipedia ... I highly recommend Bertrand Meyer's book.
robitabu:
What does actually abort() do in Arduino?
From stdlib.h:
/** The abort() function causes abnormal program termination to occur.
This realization disables interrupts and jumps to _exit() function
with argument equal to 1. In the limited AVR environment, execution is
effectively halted by entering an infinite loop. */
extern void abort(void) __ATTR_NORETURN__;
A simple error handler could be:
if (somethingBadHappens)
{
Serial.println (F("Bad thing XYZ happened."));
Serial.flush ();
exit (1);
}
The flush call will ensure the message appears before you go into the infinite loop. The F macro saves wasting valuable RAM on the message.
To ensure there is no ambiguity, I strongly agree with @PeterH...
It is never appropriate to use the AVR Libc abort.
Actually I got bitten in one of my libraries because exit() isn't always implemented. This might be neater:
if (somethingBadHappens)
{
Serial.println (F("Bad thing XYZ happened."));
Serial.flush ();
noInterrupts ();
while (true) { } // give up
}
This should get you started...
#define __ASSERT_USE_STDERR
#include <assert.h>
extern void __assert(
const char *__func,
const char *__file,
int __lineno,
const char *__sexp )
{
// Put your stuff here.
// __func is the function name (setup)
// __file is the module name (the name of your sketch)
// __lineno is the source code line number of the assert
// __sexp is the assert expression (as a C string)
Serial.print( F( "ASSERT FAILURE: " ) );
Serial.print( __file );
Serial.print( F( ": " ) );
Serial.print( __func );
Serial.print( F( ": #" ) );
Serial.print( __lineno );
Serial.println();
Serial.flush ();
noInterrupts ();
while (true) { } // give up
}
void setup( void )
{
assert( false );
}
void loop( void )
{
}
Bear in mind that each assert puts up to three string constants in SRAM. A better version would keep the string constants in Flash.
Silly me, I thought I'd need an underlying OS to abort to!
But then when I write code, I expect users to make the occasional error... since 1980.
Look on the bright side. Users expect programmers to make the occasional error, too. 
Users expect programmers to make the occasional error, too.
And I never disappoint them.
From the OLD (it was old in 85) Programmer's Joke Sheet:
Users should not complain about the code they get. They are lucky to get anything at all.
1980 is when I started writing programs for engineers. Error handling became a must!
GoForSmoke:
Users should not complain about the code they get. They are lucky to get anything at all.
Priceless!!! 