Re^2: Is the documentation for Perl 5.20 'pack' correct?

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Re^3: Is the documentation for Perl 5.20 'pack' correct? by BrowserUk (Patriarch) on Jul 07, 2015 at 07:20 UTC
Okay. I found a way to make it go away. Initialising `out` silences the warning: `#! perl -slw use strict; use Inline C => Config => BUILD_NOISY => 1; use Inline C => <<'END_C', NAME => 'Endian', CLEAN_AFTER_BUILD =>0; SV hexDump( UV in ) { int i; char p = (char)&in; SV out = newSVpvn( "?", 1 ); for( i=0; i<8; ++i ) { sv_catpvf( out, "%02x", p[i] ); } return out; } END_C print hexDump( 72623859790382856 ); __END__ C:\test>endian ?0807060504030201` [download] Which I guess means that the doc for newSVpvn() that reads:"If the s argument is NULL the new SV will be undefined. means something different to what I took it to mean. This also works: `SV hexDump( UV in ) { int i; char p = (char)&in; SV out = newSVpvn( "", 0 ); for( i=0; i<8; ++i ) { sv_catpvf( out, "%02x", p[i] ); } return out; }` [download] 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". In the absence of evidence, opinion is indistinguishable from prejudice. I'm with torvalds on this Agile (and TDD) debunked I told'em LLVM was the way to go. But did they listen!	[reply] [d/l] [select]

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Re^3: Is the documentation for Perl 5.20 'pack' correct?
by BrowserUk (Patriarch) on Jul 07, 2015 at 07:20 UTC

Okay. I found a way to make it go away. Initialising out silences the warning:

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

SV *hexDump( UV in ) {
    int i;
    char *p = (char*)&in;
    SV *out = newSVpvn( "?", 1 );

    for( i=0; i<8; ++i ) {
        sv_catpvf( out, "%02x", p[i] );
    }
    return out;
}

END_C

print hexDump( 72623859790382856 );

__END__
C:\test>endian
?0807060504030201
[download]

Which I guess means that the doc for newSVpvn() that reads:"If the s argument is NULL the new SV will be undefined. means something different to what I took it to mean.

This also works:

SV *hexDump( UV in ) {
    int i;
    char *p = (char*)&in;
    SV *out = newSVpvn( "", 0 );

    for( i=0; i<8; ++i ) {
        sv_catpvf( out, "%02x", p[i] );
    }
    return out;
}
[download]

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".

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

I'm with torvalds on this Agile (and TDD) debunked I told'em LLVM was the way to go. But did they listen!

[reply]
[d/l]
[select]