Hi,
In response to XS on 64-bit: Warning from sv_vsetpvf call almut posted some code that led me to the following Inline::C script: 
use warnings;

use Inline C => <<'EOC';

void vatest__(char* format, va_list* args) {
    char buf[1024];
    vsprintf(buf, format, *args);
    errno = 0;  // "Success"
    perror(buf);
}


void vatest_(char* format, va_list* args) {
    
    vatest__(format, args);
}


void vatest(char* format, ...) {
    va_list args;
    va_start (args, format);
    vatest_(format, &args);
    va_end (args);
}

SV * foo () {
    char* msg0 = "vatest";
    char* msg1 = "foo";
    char* msg2 = "bar";
    double d = 12.345;
    unsigned long l = 1234567890;
    vatest("%s %s", msg0, msg1);
    vatest("%s %s %s %u %f", msg0, msg1, msg2, l, d);
    return newSViv(0);
}

EOC

foo();

[download]
which outputs (on Win32): 
vatest foo: No error
vatest foo bar 1234567890 12.345000: No error

[download]
which is correct and as expected.

But then I got to wondering whether vatest() could be called directly from perl - ie, instead of having the perl section of the above script do foo(); have it do something like vatest('%s %s', 'foo', 'bar'); which would output foo bar: No error.
But, of course, that doesn't work - and I'm unable to find a way of making it work.

So, is there a way of accessing the XSub vatest() directly from perl (with either XS or Inline::C) ? I'm pretty sure there isn't ... but I'm so often wrong. Faik, there could well be some clever typemapping (or other technique) that makes it possible.

Cheers,
Rob

In reply to XS/Inline::C and ellipsis syntax by syphilis

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