Another update to the coding standard; Add some comments detailing the POSIX non-compliance in include/signal.h

2026-06-08 01:42:58 +08:00 · 2018-08-21 15:27:37 -06:00
parent 30d7dbd9a6
commit 07ef3fe018
2 changed files with 107 additions and 2 deletions
@@ -68,6 +68,62 @@
 #define SIGRTMIN        MIN_SIGNO  /* First real time signal */
 #define SIGRTMAX        MAX_SIGNO  /* Last real time signal */

+/* NuttX does not support standard signal actions.  NuttX supports only what
+ * are referred to as "real time" signals.  The default action of all NuttX
+ * signals is to simply ignore the signal.
+ *
+ * This is not POSIX compliant.  Per OpenGroup.org:  The following signals
+ * and default signal action s must be supported on all implementations:
+ *
+ *   ---------- ------- ----------------------------------------------------
+ *   Signal     Default Description
+ *   Name       Action
+ *   ---------- ------- ----------------------------------------------------
+ *   SIGABRT    A       Process abort signal
+ *   SIGALRM    T       Alarm clock
+ *   SIGBUS     A       Access to an undefined portion of a memory object
+ *   SIGCHLD    I       Child process terminated, stopped
+ *                      (or continued XSI extension)
+ *   SIGCONT    C       Continue executing, if stopped
+ *   SIGFPE     A       Erroneous arithmetic operation
+ *   SIGHUP     T       Hangup
+ *   SIGILL     A       Illegal instruction
+ *   SIGINT     T       Terminal interrupt signal
+ *   SIGKILL    T       Kill (cannot be caught or ignored)
+ *   SIGPIPE    T       Write on a pipe with no one to read it
+ *   SIGQUIT    A       Terminal quit signal
+ *   SIGSEGV    A       Invalid memory reference
+ *   SIGSTOP    S       Stop executing (cannot be caught or ignored)
+ *   SIGTERM    T       Termination signal
+ *   SIGTSTP    S       Terminal stop signal
+ *   SIGTTIN    S       Background process attempting read
+ *   SIGTTOU    S       Background process attempting write
+ *   SIGUSR1    T       User-defined signal 1
+ *   SIGUSR2    T       User-defined signal 2
+ *   SIGPOLL    T       Poll-able event (XSI extension)
+ *   SIGPROF    T       Profiling timer expired (XSI extension)
+ *   SIGSYS     A       Bad system call (XSI extension)
+ *   SIGTRAP    A       Trace/breakpoint trap (XSI extension)
+ *   SIGURG     I       High bandwidth data is available at a socket
+ *   SIGVTALRM  T       Virtual timer expired (XSI extension)
+ *   SIGXCPU    A       CPU time limit exceeded (XSI extension)
+ *   SIGXFSZ    A       File size limit exceeded (XSI extension)
+ *   ---------- ------- ----------------------------------------------------
+ *
+ * Where default action codes are:
+ *
+ * T  Abnormal termination of the process. The process is terminated with
+ *    all the consequences of _exit() except that the status made available
+ *    to wait() and waitpid() indicates abnormal termination by the
+ *    specified signal.
+ * A  Abnormal termination of the process. Additionally ith the XSI
+ *    extension, implementation-defined abnormal termination actions, such
+ *    as creation of a core file, may occur.
+ * I  Ignore the signal.
+ * S  Stop the process.
+ * C  Continue the process, if it is stopped; otherwise, ignore the signal.
+ */
+
 /* A few of the real time signals are used within the OS.  They have
 * default values that can be overridden from the configuration file. The
 * rest are all user signals.