How can I determine if a Perl function exists at runtime?

Question

I'm working on a test framework in Perl. As part of the tests, I may need to add precondition or postcondition checks for any given test, but not necessarily for all of them. What I've got so far is something like:

eval "&verify_precondition_TEST$n";
print $@ if $@;

Unfortunately, this outputs "Undefined subroutine &verify_precondition_TEST1 called at ..." if the function does not exist.

How can I determine ahead of time whether the function exists, before trying to call it?

Answer 1

With defined:

if (eval "defined(&verify_precondition_TEST$n)") {
    eval "&verify_precondition_TEST$n";
    print $@ if $@;
}
else {
    print "verify_precondition_TEST$n does not exist\n";
}

EDIT: hmm, I only thought of eval as it was in the question but with symbolic references brought up with Leon Timmermans, couldn't you do

if (defined(&{"verify_precondition_TEST$n"}) {
    &{"verify_precondition_TEST$n"};
    print $@ if $@;
}
else {
    print "verify_precondition_TEST$n does not exist\n";
}

even with strict?