diff options
Diffstat (limited to 'pod/perlvar.pod')
| -rw-r--r-- | pod/perlvar.pod | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/pod/perlvar.pod b/pod/perlvar.pod index bdf24f6c89..bfd04f74d4 100644 --- a/pod/perlvar.pod +++ b/pod/perlvar.pod @@ -38,9 +38,9 @@ new value for the FileHandle attribute in question. If not supplied, most of the methods do nothing to the current value, except for autoflush(), which will assume a 1 for you, just to be different. -A few of these variables are considered "read-only". This means that if you -try to assign to this variable, either directly or indirectly through -a reference. If you attempt to do so, you'll raise a run-time exception. +A few of these variables are considered "read-only". This means that if +you try to assign to this variable, either directly or indirectly through +a reference, you'll raise a run-time exception. =over 8 @@ -379,6 +379,9 @@ last eval() parsed and executed correctly (although the operations you invoked may have failed in the normal fashion). (Mnemonic: Where was the syntax error "at"?) +Note that warning messages are not collected in this variable. You can, +however, set up a routine to process warnings by setting $SIG{__WARN__} below. + =item $PROCESS_ID =item $PID @@ -602,7 +605,23 @@ the Perl script. Here are some other examples: The one marked scary is problematic because it's a bareword, which means sometimes it's a string representing the function, and sometimes it's going to call the subroutine call right then and there! Best to be sure -and quote it or take a reference to it. *Plumber works too. See <perlsubs>. +and quote it or take a reference to it. *Plumber works too. See L<perlsubs>. + +Certain internal hooks can be also set using the %SIG hash. The +routine indicated by $SIG{__WARN__} is called when a warning message is +about to be printed. The warning message is passed as the first +argument. The presence of a __WARN__ hook causes the ordinary printing +of warnings to STDERR to be suppressed. You can use this to save warnings +in a variable, or turn warnings into fatal errors, like this: + + local $SIG{__WARN__} = sub { die $_[0] }; + eval $proggie; + +The routine indicated by $SIG{__DIE__} is called when a fatal exception +is about to be thrown. The error message is passed as the first +argument. When a __DIE__ hook routine returns, the exception +processing continues as it would have in the absence of the hook, +unless the hook routine itself exits via a goto, a loop exit, or a die. =back |