Xcode Exit codes and signals

I've looked around and never found a comprehensive list of exit codes for Xcode especially working with iOS. This question: Debuging to simulator crashes with "exited with status 5" unless I have breakpoint simply says I need to restart xcode to solve a common problem labeled 'exit code 5'. There are many other similar questions out there. The solutions often work, however I don't understand how they work. Next time I come across once of these exit code's 开发者_JS百科I'd like to know what they mean so I can have a better idea of how to prevent it from happening again.

What are the common Xcode signals and exit codes?

signal 0 an 1 are pretty standard, others are defined in context and by users, on osx 10.6:

man signal gives:

 2     SIGINT       terminate process    interrupt program
 3     SIGQUIT      create core image    quit program
 4     SIGILL       create core image    illegal instruction
 5     SIGTRAP      create core image    trace trap
 6     SIGABRT      create core image    abort program (formerly SIGIOT)
 7     SIGEMT       create core image    emulate instruction executed
 8     SIGFPE       create core image    floating-point exception
 9     SIGKILL      terminate process    kill program
 10    SIGBUS       create core image    bus error
 11    SIGSEGV      create core image    segmentation violation
 12    SIGSYS       create core image    non-existent system call invoked
 13    SIGPIPE      terminate process    write on a pipe with no reader
 14    SIGALRM      terminate process    real-time timer expired
 15    SIGTERM      terminate process    software termination signal
 16    SIGURG       discard signal       urgent condition present on
                                         socket
 17    SIGSTOP      stop process         stop (cannot be caught or
                                         ignored)
 18    SIGTSTP      stop process         stop signal generated from
                                         keyboard
 19    SIGCONT      discard signal       continue after stop
 20    SIGCHLD      discard signal       child status has changed
 21    SIGTTIN      stop process         background read attempted from
                                         control terminal
 22    SIGTTOU      stop process         background write attempted to
                                         control terminal
 23    SIGIO        discard signal       I/O is possible on a descriptor
                                         (see fcntl(2))
 24    SIGXCPU      terminate process    cpu time limit exceeded (see
                                         setrlimit(2))
 25    SIGXFSZ      terminate process    file size limit exceeded (see
                                         setrlimit(2))
 26    SIGVTALRM    terminate process    virtual time alarm (see
                                         setitimer(2))
 27    SIGPROF      terminate process    profiling timer alarm (see
                                         setitimer(2))
 28    SIGWINCH     discard signal       Window size change
 29    SIGINFO      discard signal       status request from keyboard
 30    SIGUSR1      terminate process    User defined signal 1
 31    SIGUSR2      terminate process    User defined signal 2