---
name: compile-time syntax errors
---
# Compile-time syntax errors

Errors the parser raises before the program runs. A compile-time
error stops the whole program: nothing executes, because the
source could not be turned into runnable ops. Unlike runtime
`die`s, these are not trappable with `eval BLOCK` - but a string
`eval` of source that fails to compile reports them through `$@`:

```perl
my $code = '1 +';
eval $code;
warn "compile failed: $@" if $@;
```

## Subroutine resolution at compile time

### `` `Undefined subroutine &%s` ``

**(F)** The parser resolved a call to a named subroutine that does
not exist at compile time. This is the compile-time companion to
the runtime [`Undefined subroutine &%s called`](fatal-general)
error: the difference is *when* the missing sub is noticed. Make
sure the defining module is `use`d, and that the name is spelled
correctly and fully qualified where the package matters.

## See also

- [General fatal errors](fatal-general) - the runtime form of the
  undefined-subroutine error.
- [Subroutines](../perlsub) - declaration, prototypes, and the
  rules that decide when a call resolves.
- [`use`](../perlfunc/use) - pulls in the module that defines the
  subroutine, at compile time.