You already have a good answer but I thought I'd add on and tell you why your Win32 syntax didn't work. Its broken as-is. The use Inline C statement is executed during BEGIN-time regardless of whether the if() condition is true or not. That is, use() does a require() and import() during the compilation time and isn't affected at all about what happens later when the if() executes.

Actual results

use Inline C => DATA => NAME => 'inline_code_pl_2d59';
if ( $^O eq 'MSWin32' ) {
    # Do nothing
}
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What you could have written that would have worked on both unix and Win32.

BEGIN {
    if ( $^O eq 'MSWin32' ) {
        # Option A
        require Inline;
        Inline->import( C => DATA => NAME => 'inline_code_pl_2d59' );

        # Option B
        eval "use Inline C => DATA => NAME => 'inline_code_pl_2d59'";
        die $@ if $@;

        # Option B with line numbers that make sense if die() happens
        eval "#line " . ( 1 + __LINE __ ) . " \"" . __FILE __ . "\"\n"
              . "use Inline C => DATA => NAME => 'inline_code_pl_2d59'
+";
        die $@ if $@;
    }
}
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