source: vendor/3.5.0/lib/tdb/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;
        current_file="";
        print "#"
        print "# This file is automatically generated with \"make symbols\". DO NOT EDIT "
        print "#"
        print "{"
        print "\tglobal:"
}

END {
        print""
        print "\tlocal: *;"
        print "};"
}

{
        if (FILENAME!=current_file) {
                print "\t\t# The following definitions come from",FILENAME
                current_file=FILENAME
        }
        if (inheader) {
                if (match($0,"[)][^()]*[;][ \t]*$")) {
                        inheader = 0;
                }
                next;
        }
}

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

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

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