Re^3: perl XS - passing array to C and getting it back

I need the first option.

Then do_nothing1() below will get you started:

#! perl -slw
use strict;
use Inline C => Config => BUILD_NOISY => 1;
use Inline C => <<'END_C',  NAME => '_1159002', CLEAN_AFTER_BUILD => 0
+;

#define IS_VARS Inline_Stack_Vars
#define IS_RESET Inline_Stack_Reset
#define IS_ITEMS Inline_Stack_Items
#define IS_ITEM( n ) Inline_Stack_Item( n )
#define IS_PUSHS( s )   Inline_Stack_Push( sv_2mortal( s ) )
#define IS_PUSHIV( iv ) Inline_Stack_Push( sv_2mortal( newSViv( iv ) )
+ )
#define IS_PUSHUV( uv ) Inline_Stack_Push( sv_2mortal( newSVuv( uv ) )
+ )
#define IS_PUSHNV( nv ) Inline_Stack_Push( sv_2mortal( newSVnv( nv ) )
+ )
#define IS_DONE Inline_Stack_Done

double do_nothing1( AV *x, int sizeOfX ) {
    int index;

    for( index=0; index<sizeOfX; index++ ) {
        av_store( x, index, newSVnv( 1.0 ) );
    }
    return SvNV( *av_fetch( x, 0, NULL ) );
}

void do_nothing2( AV *a, SV *size ) {
    IS_VARS;
    int index;

    IS_RESET;
    for( index = 0; index < SvIV( size ); ++index ) {
        IS_PUSHNV( 1.0 );
    }
    IS_DONE;
}

void do_nothing3( SV*dummy, ... ) {
    IS_VARS;
    int index;

    for( index = 0; index < IS_ITEMS; ++index ) {
        IS_ITEM( index ) = newSVnv( 1.0 );
    }
    return;
}

AV *do_nothing4( AV *x ) {
    IS_VARS;
    AV *r = newAV();
    int index;

    for( index = 0; index < IS_ITEMS; ++index ) {
        av_push( r, newSVnv( SvNV( *av_fetch( x, index, NULL ) ) + 1.0
+ ) );
    }
    return r;
}

END_C

my @a = ( 0 ) x 10;

print do_nothing1( \@a, 10 );
print "@a";

my @b = ( 0 ) x 10;

print join ' ', do_nothing2( \@b, 10 );

print join ' ', do_nothing3( 1 .. 10 );

my @c = ( 1 .. 10 );

print join ' ', do_nothing4( \@c );
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If you have Inline::C installed and you run the above code you'll get this output:

C:\test>1159002.pl
1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
1 1 1 1 1 1 1 1 1 1
[download]

If you then look in the _inline directory tree created below the cwd where you run this, and look for the file _Inline/build/_1159002/_1159002.xs you'll see how it all fits together:

C:\test>type _Inline\build\_1159002\_1159002.xs
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "INLINE.h"

#define IS_VARS Inline_Stack_Vars
#define IS_RESET Inline_Stack_Reset
#define IS_ITEMS Inline_Stack_Items
#define IS_ITEM( n ) Inline_Stack_Item( n )
#define IS_PUSHS( s )   Inline_Stack_Push( sv_2mortal( s ) )
#define IS_PUSHIV( iv ) Inline_Stack_Push( sv_2mortal( newSViv( iv ) )
+ )
#define IS_PUSHUV( uv ) Inline_Stack_Push( sv_2mortal( newSVuv( uv ) )
+ )
#define IS_PUSHNV( nv ) Inline_Stack_Push( sv_2mortal( newSVnv( nv ) )
+ )
#define IS_DONE Inline_Stack_Done

double do_nothing1( AV *x, int sizeOfX ) {
    int index;

    for( index=0; index<sizeOfX; index++ ) {
        av_store( x, index, newSVnv( 1.0 ) );
    }
    return SvNV( *av_fetch( x, 0, NULL ) );
}

void do_nothing2( AV *a, SV *size ) {
    IS_VARS;
    int index;

    IS_RESET;
    for( index = 0; index < SvIV( size ); ++index ) {
        IS_PUSHNV( 1.0 );
    }
    IS_DONE;
}

void do_nothing3( SV*dummy, ... ) {
    IS_VARS;
    int index;

    for( index = 0; index < IS_ITEMS; ++index ) {
        IS_ITEM( index ) = newSVnv( 1.0 );
    }
    return;
}

AV *do_nothing4( AV *x ) {
    IS_VARS;
    AV *r = newAV();
    int index;

    for( index = 0; index < IS_ITEMS; ++index ) {
        av_push( r, newSVnv( SvNV( *av_fetch( x, index, NULL ) ) + 1.0
+ ) );
    }
    return r;
}


MODULE = _1159002  PACKAGE = main

PROTOTYPES: DISABLE


double
do_nothing1 (x, sizeOfX)
        AV *    x
        int     sizeOfX

void
do_nothing2 (a, size)
        AV *    a
        SV *    size
        PREINIT:
        I32* temp;
        PPCODE:
        temp = PL_markstack_ptr++;
        do_nothing2(a, size);
        if (PL_markstack_ptr != temp) {
          /* truly void, because dXSARGS not invoked */
          PL_markstack_ptr = temp;
          XSRETURN_EMPTY; /* return empty stack */
        }
        /* must have used dXSARGS; list context implied */
        return; /* assume stack size is correct */

void
do_nothing3 (dummy, ...)
        SV *    dummy
        PREINIT:
        I32* temp;
        PPCODE:
        temp = PL_markstack_ptr++;
        do_nothing3(dummy);
        if (PL_markstack_ptr != temp) {
          /* truly void, because dXSARGS not invoked */
          PL_markstack_ptr = temp;
          XSRETURN_EMPTY; /* return empty stack */
        }
        /* must have used dXSARGS; list context implied */
        return; /* assume stack size is correct */

AV *
do_nothing4 (x)
        AV *    x
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With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

Comment on Re^3: perl XS - passing array to C and getting it back Select or Download Code

Replies are listed 'Best First'.
Re^4: perl XS - passing array to C and getting it back by kopolov (Acolyte) on Mar 29, 2016 at 13:11 UTC
Assume I am really really (!!!) dumb. I can't use inline at all. It has to be perl XSUB which calls C function and pass it an array. can it be done?	[reply]
Re^5: perl XS - passing array to C and getting it back by Corion (Patriarch) on Mar 29, 2016 at 13:20 UTC
The easy approach is to install and use Inline::C to generate the XS scaffolding for your code. After that, you throw away Inline::C and only use its output. If you don't know how to install Inline::C, the easy approach is outlined in the following steps: Install local::lib (because you don't want to pollute the system Perl) Set your environment variables like `local::lib` proposes Download `cpanm` from http://cpanmin.us Run the following command: `cpanm Inline::C` [download] You now have Inline::C and its prerequisites installed in a local directory and can use Inline::C to generate much of the XS code for you.	[reply] [d/l] [select]
Re^5: perl XS - passing array to C and getting it back by BrowserUk (Patriarch) on Mar 29, 2016 at 13:35 UTC
I can't use inline at all. That's why I posted the .xs file generated by Inline::C. You'll need to grab Inline.h from the package and then the XS code I posted should compile directly. Of course, if you can compile XS code, there is no rational reason why you cannot use Inline::C; but if you prefer not to that's your choice. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :) In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^5: perl XS - passing array to C and getting it back by Tux (Canon) on Mar 29, 2016 at 13:56 UTC
If you take the path of real XS code, be sure to use Devel::PPPort from the start. It'll save you a lot of headaches later. Then read the docs (twice): `$ perldoc perlxs $ perldoc perlxstut $ perldoc perlxstypemap` [download] Enjoy, Have FUN! H.Merijn	[reply] [d/l]