iphone - Exception Types in iOS crash logs

Question

I've seen a few different types of crash logs since I begin learning iOS development.

I know that: Exception Type: EXC_BAD_ACCESS (SIGSEGV) mean we are accessing a released object.

but don't know about:
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Type: EXC_CRASH (SIGABRT)
Exception Type: EXC_BREAKPOINT (SIGTRAP)

Do you know how many Exception Types in iOS crash logs and what do they mean?

Answer 1

I know that: Exception Type: EXC_BAD_ACCESS (SIGSEGV) mean we are accessing a released object.

No.

A SIGSEGV is a segmentation fault, meaning you are trying to access an invalid memory address.

Those exceptions (in fact, they are signals) are not related to Objective-C, but C. So you can get such an exception without Objective-C objects.

Note that a signal is not an exception, meaning you can't catch them with @try and @catch blocks.

You may set a signal handler with the signal and sigaction functions. Keep in mind some signals, like SIGABRT cannot be blocked.

You can check the Wikipedia page about signals, if you want more informations.

That said, to resume:

SIGSEGV (Segmentation fault)

Access to an invalid memory address. The address exist, but your program does not have access to it.

SIGBUS (Bus error)

Access to an invalid memory address. The address does not exist, or the alignment is invalid.

SIGFPE (Floating point exception)

Invalid arithmetic operation. Can be related to integer operations, despite the name.

SIGPIPE

Broken pipe.

SIGILL

Illegal processor instruction.

SIGTRAP

Debugger related

SIGABRT

Program crash, not related to one of the preceding signal.