Very Computer

I'm having trouble getting the Sparcworks 4.X compiler to compile
POSIX.1 signal handling code (an example is at the end of this message).

It appears that the sys/signal.h declaration for the sigaction struct
is in error, in that sigaction.sa_handler is declared as a void(*)()
rather than a void(*)(int).

As I understand it, this declaration works fine under "ANSI" or "standard"
C, but under C++ a () argument declaration is the SAME as (void), unlike
"ANSI" or "standard" C.

For now, I've "casted-away" this problem, but would like to have a cleaner
solution. Note that gcc and other compilers on other platforms do not
exhibit
this symptom.

**example.c:
#include <signal.h>

void signal_handler(int)
{

Quote:}

void funct()
{
  struct sigaction        action;

  action.sa_handler = signal_handler; /*ERROR: cannot assign void(*)(int)
to void(*)()*/

  action.sa_handler = SIG_IGN; /*ERROR: cannot assign void(*)(int) to
void(*)()*/

Quote:}

- - - -
**sys/signal.h:
struct sigaction {
        int sa_flags;
        union {
                void (*_handler)();
        }       _funcptr;

Quote:};

#define sa_handler      _funcptr._handler
- - - -

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Open Port Technology

I got an answer from Sun admitting a C++ incompatibility in
signal.h:
- - - -
From /usr/include/sys/signal.h (On Solaris 2.5 - not yet released):

Both are incorrect :-(

/*
 * The signal handler routine can have either one or three arguments.
 * Existing C code has used either form so not specifing the arguments
 * neatly finesses the problem.  C++ doesn't accept this.  To C++
 * "(*sa_handler)()" indicates a routine with no arguments (ANSI C would
 * specify this as "(*sa_handler)(void)").  One or the other form must be
 * used for C++ and the only logical choice is "(*sa_handler)(int)" to
allow
 * the SIG_* defines to work.  "(*sa_sigaction)(int, siginfo_t *, void *)"
 * can be used for the three argument form.
 */

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URL: http://www.mcs.com/~buc/home.html URL:
ftp://ftp.mcs.com/mcsnet.users/buc/

That's a bug in Sun's include files;

change it to read:

#ifdef  __cplusplus
                void (*_handler)(int);
#else
                void (*_handler)();
#endif

instead of just:

                void (*_handler)();

(Though the __cplusplus branch should really also be used for ANSI C)

Casper
--
Expressed in this posting are my opinions.  They are in no way related
to opinions held by my employer, Sun Microsystems.