in reply to return undef

I can't make sense of your question. If myfunction() returns a filehandle, then it is out of place in an expression like 

print FILEHANDLE myfunction();

[download]
unless you want your output to look something like GLOB(0x1234567).

I think that what you want is something like 

my $output_handle = myfunction();
if ( $output_handle ) {
  print $output_handle $whatever;
}
else {
  # deal with null-handle error
}

[download]

the lowliest monk

Replies are listed 'Best First'.
Re^2: return undef
by dwijew (Initiate) on May 23, 2005 at 02:49 UTC
    when i use print FILEHANDLE myfunction(); the file that is being sent from my function gets copied into FILEHANDLE. thats what i want it to do. however if there is an error myfunction() returns undef. my question is how do i check if it is returning the filehandle or undef? in order to copy the file or display the error message?
[reply]
[d/l]
      Ah, you've confused people with your terminology. You seem to mean that the function reads from a filehandle and returns the contents. Is this correct?

      If so, something like: 

      my $filedata = myfunction();
if (defined $filedata) {
   print FILEHANDLE $filedata;
} else {
   # handle error...
}

      [download]
      P.S. Showing some or all of myfunction() would really help us help you.
[reply]
[d/l]

      I think you are confusing the meaning of copying filehandles with that of copying the contents from one file to another.

      I am guessing that it is the latter that you really want. I assume that myfunction returns either an open read handle or undef. In this case, you can do something like 

      my $in = myfunction();
if ( $in ) {
  print FILEHANDLE while <$in>;
}
else {
  # handle null-handle error;
}

      [download]

      the lowliest monk

[reply]
[d/l]
        how would i return an open filehandle through a functon? aren't you supposed to send the contents of the file?
[reply]
      There is a module for this: File::Slurp.


      holli, /regexed monk/
[reply]
[d/l]

In Section Seekers of Perl Wisdom