SPARC and SA_SIGINFO signal handling

[Christophe Rhodes <csr21@cam.ac.uk>]

Dear all,

I'm having trouble on SPARC/Linux (of both the 32 and 64 varieties)
getting at the third argument of POSIX sa_sigaction signal handlers.

Consider the following code (a simplified version of what I'm actually
trying to do):
--- Cut here ---
#include <stdlib.h>
#include <sys/ucontext.h>
#include <signal.h>

void sigsegv_handler (int signo, siginfo_t *info, void *data) {
  return;
}

int main () {
  int *foo;
  struct sigaction sa;

  sa.sa_sigaction = sigsegv_handler;
  sa.sa_flags = SA_SIGINFO | SA_RESTART;
  sigaction(SIGSEGV, &sa, NULL);

  foo = NULL;
  *foo = 3;
  return 0;
}
--- Cut here ---
Running under gdb reveals that, whereas on alpha, x86 and ppc the
third argument to sigsegv_handler is a pointer to a ucontext
structure, on sparc and sparc64 I get NULL.

Am I doing something wrong, or is the ucontext argument simply not yet
implemented on the sparc architecture?

Many thanks,

Christophe
-- 
Jesus College, Cambridge, CB5 8BL                           +44 1223 510 299
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