source: vendor/3.6.0/lib/talloc/script/mksyms.awk

#
# mksyms.awk
#
# Extract symbols to export from C-header files.
# output in version-script format for linking shared libraries.
#
# Copyright (C) 2008 Micheal Adam <obnox@samba.org>
#
BEGIN {
        inheader=0;
        indoxygen=0;
}

END {
}

{
        if (inheader) {
                if (match($0,"[)][^()]*[;][ \t]*$")) {
                        inheader = 0;
                }
                next;
        }
        if (indoxygen) {
                if (match($0,"^#[ \t]*else[ \t]*.*$")) {
                        indoxygen = 0;
                }
                next;
        }
}

/^static/ || /^[ \t]*typedef/ || !/^[a-zA-Z\_\#]/ {
        next;
}

/^extern[ \t]+[^()]+[;][ \t]*$/ {
        gsub(/[^ \t]+[ \t]+/, "");
        sub(/[;][ \t]*$/, "");
        printf "           %s;\n", $0;
        next;
}

/^#[ \t]*ifdef[ \t]*DOXYGEN[ \t]*.*$/ {
        indoxygen=1;
        next;
}

# look for function headers:
{
        gotstart = 0;
        if ($0 ~ /^[A-Za-z_][A-Za-z0-9_]+/) {
                gotstart = 1;
        }
        if(!gotstart) {
                next;
        }
}

/[_A-Za-z0-9]+[ \t]*[(].*[)][^()]*;[ \t]*$/ {
        sub(/[(].*$/, "");
        gsub(/[^ \t]+[ \t]+/, "");
        gsub(/^[*]+/, "");
        printf "           %s;\n",$0;
        next;
}

/[_A-Za-z0-9]+[ \t]*[(]/ {
        inheader=1;
        sub(/[(].*$/, "");
        gsub(/[^ \t]+[ \t]+/, "");
        gsub(/^[*]/, "");
        printf "           %s;\n",$0;
        next;
}