-//depot/perl/pod/perldiag.pod#272 - edit change 14824 (text)
=head1 NAME
perldiag - various Perl diagnostics
=over 4
+=item A thread exited while %d other threads were still running
+
+(W) When using threaded Perl, a thread (not necessarily the main
+thread) exited while there were still other threads running.
+Usually it's a good idea to first collect the return values of the
+created threads by joining them, and only then exit from the main
+thread. See L<threads>.
+
=item accept() on closed socket %s
(W closed) You tried to do an accept on a closed socket. Did you forget
name, and not a subroutine call. C<exists &sub()> will generate this
error.
+=item '%s' trapped by operation mask
+
+(F) You tried to use an operator from a Safe compartment in which it's
+disallowed. See L<Safe>.
+
=item Argument "%s" isn't numeric%s
(W numeric) The indicated string was fed as an argument to an operator
must either both be scalars or both be lists. Otherwise Perl won't
know which context to supply to the right side.
-=item Attempt to access disallowed key '%s' in a fixed hash
+=item Attempt to access disallowed key '%s' in a restricted hash
(F) The failing code has attempted to get or set a key which is not in
-the current set of allowed keys of a fixed hash.
+the current set of allowed keys of a restricted hash.
-=item Attempt to clear a fixed hash
+=item Attempt to clear a restricted hash
-(F) It is currently not allowed to clear a fixed hash, even if the
+(F) It is currently not allowed to clear a restricted hash, even if the
new hash would contain the same keys as before. This may change in
the future.
-=item Attempt to delete readonly key '%s' from a fixed hash
+=item Attempt to delete readonly key '%s' from a restricted hash
(F) The failing code attempted to delete a key whose value has been
-declared readonly from a fixed hash.
+declared readonly from a restricted hash.
-=item Attempt to delete disallowed key '%s' from a fixed hash
+=item Attempt to delete disallowed key '%s' from a restricted hash
-(F) The failing code attempted to delete from a fixed hash a key which
-is not in its key set.
+(F) The failing code attempted to delete from a restricted hash a key
+which is not in its key set.
=item Attempt to bless into a reference
(P) One of the internal hash routines was passed a null HV pointer.
-=item Bad index while coercing array into hash
-
-(F) The index looked up in the hash found as the 0'th element of a
-pseudo-hash is not legal. Index values must be at 1 or greater.
-See L<perlref>.
-
=item Badly placed ()'s
(A) You've accidentally run your script through B<csh> instead
function correctly, you may put an ampersand before the name to avoid
the warning. See L<perlsub>.
+=item Can only compress unsigned integers
+
+(F) An argument to pack("w",...) was not an integer. The BER compressed
+integer format can only be used with positive integers, and you attempted
+to compress something else. See L<perlfunc/pack>.
+
+=item Cannot compress integer
+
+(F) An argument to pack("w",...) was too large to compress. The BER
+compressed integer format can only be used with positive integers, and you
+attempted to compress Infinity or a very large number (> 1e308).
+See L<perlfunc/pack>.
+
+=item Cannot compress negative numbers
+
+(F) An argument to pack("w",...) was negative. The BER compressed integer
+format can only be used with positive integers. See L<perlfunc/pack>.
+
=item / cannot take a count
(F) You had an unpack template indicating a counted-length string, but
=item Can't find %s property definition %s
-(F) You may have tried to use C<\p> which means a Unicode property for
-example \p{Lu} is all uppercase letters. if you did mean to use a
+(F) You may have tried to use C<\p> which means a Unicode property (for
+example C<\p{Lu}> is all uppercase letters). If you did mean to use a
Unicode property, see L<perlunicode> for the list of known properties.
If you didn't mean to use a Unicode property, escape the C<\p>, either
-C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, until
+by C<\\p> (just the C<\p>) or by C<\Q\p> (the rest of the string, until
possible C<\E>).
=item Can't fork
localize a package variable of the same name, qualify it with the
package name.
-=item Can't localize pseudo-hash element
-
-(F) You said something like C<< local $ar->{'key'} >>, where $ar is a
-reference to a pseudo-hash. That hasn't been implemented yet, but you
-can get a similar effect by localizing the corresponding array element
-directly -- C<< local $ar->[$ar->[0]{'key'}] >>.
-
=item Can't localize through a reference
(F) You said something like C<local $$ref>, which Perl can't currently
functioning as a class, but that package doesn't define that particular
method, nor does any of its base classes. See L<perlobj>.
+=item Can't locate PerlIO%s
+
+(F) You tried to use in open() a PerlIO layer that does not exist,
+e.g. open(FH, ">:nosuchlayer", "somefile").
+
=item (perhaps you forgot to load "%s"?)
(F) This is an educated guess made in conjunction with the message
is because you don't have read permission for a file which you named on
the command line.
+=item Can't open a reference
+
+(W io) You tried to open a scalar reference for reading or writing,
+using the 3-arg open() syntax :
+
+ open FH, '>', $ref;
+
+but your version of perl is compiled without perlio, and this form of
+open is not supported.
+
=item Can't open bidirectional pipe
(W pipe) You tried to say C<open(CMD, "|cmd|")>, which is not supported.
that it is simpler or backtracks less. (See L<perlfaq2> for information
on I<Mastering Regular Expressions>.)
+=item cond_broadcast() called on unlocked variable
+
+(W threads) Within a thread-enabled program, you tried to call
+cond_broadcast() on a variable which wasn't locked. The cond_broadcast()
+function is used to wake up another thread that is waiting in a
+cond_wait(). To ensure that the signal isn't sent before the other thread
+has a chance to enter the wait, it is usual for the signaling thread to
+first wait for a lock on variable. This lock attempt will only succeed
+after the other thread has entered cond_wait() and thus relinquished the
+lock.
+
+
+=item cond_signal() called on unlocked variable
+
+(W threads) Within a thread-enabled program, you tried to call
+cond_signal() on a variable which wasn't locked. The cond_signal()
+function is used to wake up another thread that is waiting in a
+cond_wait(). To ensure that the signal isn't sent before the other thread
+has a chance to enter the wait, it is usual for the signaling thread to
+first wait for a lock on variable. This lock attempt will only succeed
+after the other thread has entered cond_wait() and thus relinquished the
+lock.
+
=item connect() on closed socket %s
(W closed) You tried to do a connect on a closed socket. Did you forget
=item Constant subroutine %s redefined
-(S|W redefine) You redefined a subroutine which had previously been
+(S) You redefined a subroutine which had previously been
eligible for inlining. See L<perlsub/"Constant Functions"> for
commentary and workarounds.
=item Exiting format via %s
-(W exiting) You are exiting an eval by unconventional means, such as a
+(W exiting) You are exiting a format by unconventional means, such as a
goto, or a loop control statement.
=item Exiting pseudo-block via %s
=item Filehandle %s opened only for input
-(W io) You tried to write on a read-only filehandle. If you intended it
-to be a read-write filehandle, you needed to open it with "+<" or "+>"
-or "+>>" instead of with "<" or nothing. If you intended only to write
-the file, use ">" or ">>". See L<perlfunc/open>.
+(W io) You tried to write on a read-only filehandle. If you intended
+it to be a read-write filehandle, you needed to open it with "+<" or
+"+>" or "+>>" instead of with "<" or nothing. If you intended only to
+
write the file, use ">" or ">>". See L<perlfunc/open>.
=item Filehandle %s opened only for output
-(W io) You tried to read from a filehandle opened only for writing. If
+(W io) You tried to read from a filehandle opened only for writing, If
you intended it to be a read/write filehandle, you needed to open it
with "+<" or "+>" or "+>>" instead of with "<" or nothing. If you
intended only to read from the file, use "<". See L<perlfunc/open>.
+Another possibility is that you attempted to open filedescriptor 0
+(also known as STDIN) for output (maybe you closed STDIN earlier?).
+
+=item Filehandle %s reopened as %s only for input
+
+(W io) You opened for reading a filehandle that got the same filehandle id
+as STDOUT or STDERR. This occured because you closed STDOUT or STDERR
+previously.
+
+=item Filehandle STDIN reopened as %s only for output
+
+(W io) You opened for writing a filehandle that got the same filehandle id
+as STDIN. This occured because you closed STDIN previously.
=item Final $ should be \$ or $name
(W syntax) An illegal character was found in a prototype declaration. Legal
characters in prototypes are $, @, %, *, ;, [, ], &, and \.
+=item Illegal declaration of anonymous subroutine
+
+(F) When using the C<sub> keyword to construct an anonymous subroutine,
+you must always specify a block of code. See L<perlsub>.
+
=item Illegal division by zero
(F) You tried to divide a number by 0. Either something was wrong in
(F) You can't use system(), exec(), or a piped open in a setuid or
setgid script if any of C<$ENV{PATH}>, C<$ENV{IFS}>, C<$ENV{CDPATH}>,
-C<$ENV{ENV}> or C<$ENV{BASH_ENV}> are derived from data supplied (or
-potentially supplied) by the user. The script must set the path to a
-known value, using trustworthy data. See L<perlsec>.
+C<$ENV{ENV}>, C<$ENV{BASH_ENV}> or C<$ENV{TERM}> are derived from data
+supplied (or potentially supplied) by the user. The script must set
+
the path to a known value, using trustworthy data. See L<perlsec>.
=item Integer overflow in %s number
internally--subject to loss of precision errors in subsequent
operations.
+=item Integer overflow in version
+
+(F) Some portion of a version initialization is too large for the
+size of integers for your architecture. This is not a warning
+because there is no rational reason for a version to try and use a
+element larger than typically 2**32. This is usually caused by
+trying to use some odd mathematical operation as a version, like
+100/9.
+
=item Internal disaster in regex; marked by <-- HERE in m/%s/
(P) Something went badly wrong in the regular expression parser.
up to C<ff>. The <-- HERE shows in the regular expression about where the
problem was discovered. See L<perlre>.
-=item Invalid [] range "%s" in transliteration operator
+=item Invalid range "%s" in transliteration operator
(F) The range specified in the tr/// or y/// operator had a minimum
character greater than the maximum character. See L<perlop>.
(W unpack) The given character is not a valid unpack type but used to be
silently ignored.
+=item Invalid version format (multiple underscores)
+
+(F) Versions may contain at most a single underscore, which signals
+that the version is a beta release. See L<version> for the allowed
+version formats.
+
+=item Invalid version format (underscores before decimal)
+
+(F) Versions may not contain decimals after the optional underscore.
+See L<version> for the allowed version formats.
+
=item ioctl is not implemented
(F) Your machine apparently doesn't implement ioctl(), which is pretty
C<open(FH, "command |")> construction, but the command was missing or
blank.
+=item Missing control char name in \c
+
+(F) A double-quoted string ended with "\c", without the required control
+character name.
+
=item Missing name in "my sub"
(F) The reserved syntax for lexically scoped subroutines requires that
close a pipe which hadn't been opened. This should have been caught
earlier as an attempt to close an unopened filehandle.
-=item No such pseudo-hash field "%s"
-
-(F) You tried to access an array as a hash, but the field name used is
-not defined. The hash at index 0 should map all valid field names to
-array indices for that to work.
-
-=item No such pseudo-hash field "%s" in variable %s of type %s
-
-(F) You tried to access a field of a typed variable where the type does
-not know about the field name. The field names are looked up in the
-%FIELDS hash in the type package at compile time. The %FIELDS hash is
-%usually set up with the 'fields' pragma.
-
=item No such signal: SIG%s
(W signal) You specified a signal name as a subscript to %SIG that was
=item perlio: argument list not closed for layer "%s"
-(S) When pushing a layer with arguments onto the Perl I/O system you forgot
-the ) that closes the argument list. (Layers take care of transforming
+(W layer) When pushing a layer with arguments onto the Perl I/O system you
+forgot the ) that closes the argument list. (Layers take care of transforming
data between external and internal representations.) Perl stopped parsing
the layer list at this point and did not attempt to push this layer.
If your program didn't explicitly request the failing operation, it may be
the result of the value of the environment variable PERLIO.
-=item perlio: invalid separator character %s in attribute list
+=item perlio: invalid separator character %s in layer specification list %s
-(S) When pushing layers onto the Perl I/O system, something other than a
+(W layer) When pushing layers onto the Perl I/O system, something other than a
colon or whitespace was seen between the elements of a layer list.
If the previous attribute had a parenthesised parameter list, perhaps that
list was terminated too soon.
=item perlio: unknown layer "%s"
-(S) An attempt was made to push an unknown layer onto the Perl I/O
+(W layer) An attempt was made to push an unknown layer onto the Perl I/O
system. (Layers take care of transforming data between external and
internal representations.) Note that some layers, such as C<mmap>,
are not supported in all environments. If your program didn't
end of the buffer just in case. This sentinel byte got clobbered, and
Perl assumes that memory is now corrupted. See L<perlfunc/ioctl>.
+=item Possible precedence problem on bitwise %c operator
+
+(W precedence) Your program uses a bitwise logical operator in conjunction
+with a numeric comparison operator, like this :
+
+ if ($x & $y == 0) { ... }
+
+This expression is actually equivalent to C<$x & ($y == 0)>, due to the
+higher precedence of C<==>. This is probably not what you want. (If you
+really meant to write this, disable the warning, or, better, write
+C<$x & ($y == 0 ? 1 : 0)>).
+
=item Possible unintended interpolation of %s in string
(W ambiguous) You said something like `@foo' in a double-quoted string
=item Prototype not terminated
-(F) You've omitted the closing parenthesis in a function prototype
+(F) You've omitted the closing parenthesis in a function prototype
definition.
=item Quantifier in {,} bigger than %d in regex;
One possible workaround is to force Perl to use magical string increment
by prepending "0" to your numbers.
+=item read() on closed filehandle %s
+
+(W closed) You tried to read from a closed filehandle.
+
+=item read() on unopened filehandle %s
+
+(W unopened) You tried to read from a filehandle that was never opened.
+
=item readline() on closed filehandle %s
(W closed) The filehandle you're reading from got itself closed sometime
construct. Remember that bracketing delimiters count nesting level.
Missing the leading C<$> from a variable C<$m> may cause this error.
+Note that since Perl 5.9.0 a // can also be the I<defined-or>
+construct, not just the empty search pattern. Therefore code written
+in Perl 5.9.0 or later that uses the // as the I<defined-or> can be
+misparsed by pre-5.9.0 Perls as a non-terminated search pattern.
+
=item %sseek() on unopened filehandle
(W unopened) You tried to use the seek() or sysseek() function on a
(F) The final summary message when a C<perl -c> succeeds.
+=item sysread() on closed filehandle %s
+
+(W closed) You tried to read from a closed filehandle.
+
+=item sysread() on unopened filehandle %s
+
+(W unopened) You tried to read from a filehandle that was never opened.
+
=item System V %s is not implemented on this machine
(F) You tried to do something with a function beginning with "sem",
target of the change to
%ENV which produced the warning.
+=item thread failed to start: %s
+
+(F) The entry point function of threads->create() failed for some reason.
+
=item times not implemented
(F) Your version of the C library apparently doesn't do times(). I
suspect you're not running on Unix.
+=item To%s: illegal mapping '%s'
+
+(F) You tried to define a customized To-mapping for lc(), lcfirst,
+uc(), or ucfirst() (or their string-inlined versions), but you
+specified an illegal mapping.
+See L<perlunicode/"User-Defined Character Properties">.
+
=item Too few args to syscall
(F) There has to be at least one argument to syscall() to specify the
(F) The second argument of 3-argument open() is not among the list
of valid modes: C<< < >>, C<< > >>, C<<< >> >>>, C<< +< >>,
-C<< +> >>, C<<< +>> >>>, C<-|>, C<|->.
+C<< +> >>, C<<< +>> >>>, C<-|>, C<|->, C<< <& >>, C<< >& >>.
=item Unknown process %x sent message to prime_env_iter: %s
data Perl expected. Someone's very confused, or perhaps trying to
subvert Perl's population of %ENV for nefarious purposes.
+=item Unknown Unicode option letter '%c'
+
+You specified an unknown Unicode option. See L<perlrun> documentation
+of the C<-C> switch for the list of known options.
+
+=item Unknown Unicode option value %x
+
+You specified an unknown Unicode option. See L<perlrun> documentation
+of the C<-C> switch for the list of known options.
+
=item Unknown warnings category '%s'
(F) An error issued by the C<warnings> pragma. You specified a warnings
use the /g modifier. Currently, /c is meaningful only when /g is
used. (This may change in the future.)
+=item Use of /g modifier is meaningless in split
+
+(W regexp) You used the /g modifier on the pattern for a C<split>
+operator. Since C<split> always tries to match the pattern
+repeatedly, the C</g> has no effect.
+
=item Use of *glob{FILEHANDLE} is deprecated
(D deprecated) You are now encouraged to use the shorter *glob{IO} form
=item Use of reference "%s" as array index
-(W) You tried to use a reference as an array index; this probably
+(W misc) You tried to use a reference as an array index; this probably
isn't what you mean, because references in numerical context tend
to be huge numbers, and so usually indicates programmer error.
=item Use of tainted arguments in %s is deprecated
-(W taint) You have supplied C<system()> or C<exec()> with multiple
+(W taint, deprecated) You have supplied C<system()> or C<exec()> with multiple
arguments and at least one of them is tainted. This used to be allowed
but will become a fatal error in a future version of perl. Untaint your
arguments. See L<perlsec>.
=item v-string in use/require is non-portable
-(W) The use of v-strings is non-portable to older, pre-5.6, Perls.
+(W portable) The use of v-strings is non-portable to older, pre-5.6, Perls.
If you want your scripts to be backward portable, use the floating
point version number: for example, instead of C<use 5.6.1> say
C<use 5.006_001>. This of course won't help: the older Perls
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