# ....

# use perl to get your data into an array however suits 
#  your needs (from a file, DBI, etc.)

@array = (1,2,3,4,5,6,7,23);  # for example

# sample case where the C function is signed-int-based
$packed_as_ints = pack("i*",@array);
# note that with C and arrays, you need to pass the number 
# of elements along too
$result = fast_c_function_int($packed_as_ints,scalar(@array));

# here is a sample case using doubles
$packed_as_doubles = pack("d*",@array);
$result = fast_c_function_double($packed_as_doubles,scalar(@array));

# etc.  -- this technique can work for any primitive 
# datatype that can be represented natively (byte, short, etc)
# see perldoc -f pack for the codes to pack to any of the 
# native data types (note where you need the "!" to force 
# native packing, though!)

use Inline C => <<'END_OF_C_CODE';

double fast_c_function_int(char * the_data, int nelems) {
    int *real_data = (int *) the_data;
    double result;
    /*  do your fast calculation here */
    return result;
}
double fast_c_function_double(char * the_data, int nelems) {
    double *real_data = (double *) the_data;
    double result;
    /*  do your fast calculation here */
    return result;
}

END_OF_C_CODE