diff options
Diffstat (limited to 'pod/perldiag.pod')
| -rw-r--r-- | pod/perldiag.pod | 148 |
1 files changed, 85 insertions, 63 deletions
diff --git a/pod/perldiag.pod b/pod/perldiag.pod index 20f4fbd585..bbd699faaa 100644 --- a/pod/perldiag.pod +++ b/pod/perldiag.pod @@ -53,7 +53,7 @@ no useful value. See L<perlmod>. =item % may only be used in unpack -(F) You can't pack a string by supplying a checksum, since the +(F) You can't pack a string by supplying a checksum, because the checksumming process loses information, and you can't go the other way. See L<perlfunc/unpack>. @@ -61,15 +61,27 @@ way. See L<perlfunc/unpack>. (W) You've run afoul of the rule that says that any list operator followed by parentheses turns into a function, with all the list operators arguments -found inside the parens. See L<perlop/Terms and List Operators (Leftward)>. +found inside the parentheses. See L<perlop/Terms and List Operators (Leftward)>. =item %s argument is not a HASH element -(F) The argument to delete() or exists() must be a hash element, such as +(F) The argument to exists() must be a hash element, such as $foo{$bar} $ref->[12]->{"susie"} +=item %s argument is not a HASH element or slice + +(F) The argument to delete() must be either a hash element, such as + + $foo{$bar} + $ref->[12]->{"susie"} + +or a hash slice, such as + + @foo{$bar, $baz, $xyzzy} + @{$ref->[12]}{"susie", "queue"} + =item %s did not return a true value (F) A required (or used) file must return a true value to indicate that @@ -176,7 +188,7 @@ the return value of your socket() call? See L<perlfunc/accept>. (W)(S) You said something that may not be interpreted the way you thought. Normally it's pretty easy to disambiguate it by supplying -a missing quote, operator, paren pair or declaration. +a missing quote, operator, parenthesis pair or declaration. =item Args must match #! line @@ -252,7 +264,7 @@ dereference it first. See L<perlfunc/substr>. (F) You passed a buffer of the wrong size to one of msgctl(), semctl() or shmctl(). In C parlance, the correct sizes are, respectively, -S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)> and +S<sizeof(struct msqid_ds *)>, S<sizeof(struct semid_ds *)>, and S<sizeof(struct shmid_ds *)>. =item Bad associative array @@ -336,7 +348,7 @@ exited by calling exit. except that there's this itty bitty problem called there isn't a current block. Note that an "if" or "else" block doesn't count as a "loopish" block. You can usually double the curlies to get the same -effect though, since the inner curlies will be considered a block +effect though, because the inner curlies will be considered a block that loops once. See L<perlfunc/last>. =item Can't "next" outside a block @@ -344,7 +356,7 @@ that loops once. See L<perlfunc/last>. (F) A "next" statement was executed to reiterate the current block, but there isn't a current block. Note that an "if" or "else" block doesn't count as a "loopish" block. You can usually double the curlies to get -the same effect though, since the inner curlies will be considered a block +the same effect though, because the inner curlies will be considered a block that loops once. See L<perlfunc/last>. =item Can't "redo" outside a block @@ -352,7 +364,7 @@ that loops once. See L<perlfunc/last>. (F) A "redo" statement was executed to restart the current block, but there isn't a current block. Note that an "if" or "else" block doesn't count as a "loopish" block. You can usually double the curlies to get -the same effect though, since the inner curlies will be considered a block +the same effect though, because the inner curlies will be considered a block that loops once. See L<perlfunc/last>. =item Can't bless non-reference value @@ -427,14 +439,14 @@ or other plumbing problems. =item Can't declare %s in my -(F) Only scalar, array and hash variables may be declared as lexical variables. +(F) Only scalar, array, and hash variables may be declared as lexical variables. They must have ordinary identifiers as names. =item Can't do inplace edit on %s: %s (S) The creation of the new file failed for the indicated reason. -=item Can't do inplace edit without backup +=item Can't do in-place edit without backup (F) You're on a system such as MSDOS that gets confused if you try reading from a deleted (but still opened) file. You have to say B<-i>C<.bak>, or some @@ -484,7 +496,7 @@ For example, it'd be kind of silly to put a B<-x> on the #! line. =item Can't exec "%s": %s -(W) An system(), exec() or piped open call could not execute the named +(W) An system(), exec(), or piped open call could not execute the named program for the indicated reason. Typical reasons include: the permissions were wrong on the file, the file wasn't found in C<$ENV{PATH}>, the executable in question was compiled for another architecture, or the @@ -510,7 +522,7 @@ for us to go to. See L<perlfunc/goto>. =item Can't find string terminator %s anywhere before EOF (F) Perl strings can stretch over multiple lines. This message means that -the closing delimiter was omitted. Since bracketed quotes count nesting +the closing delimiter was omitted. Because bracketed quotes count nesting levels, the following is missing its final parenthesis: print q(The character '(' starts a side comment.) @@ -537,7 +549,7 @@ assumes that the stat buffer contains all the necessary information, and passes it, instead of the filespec, to the access checking routine. It will try to retrieve the filespec using the device name and FID present in the stat buffer, but this works only if you haven't made a subsequent call to the CRTL stat() -routine, since the device name is overwritten with each call. If this warning +routine, because the device name is overwritten with each call. If this warning appears, the name lookup failed, and the access checking routine gave up and returned FALSE, just to be conservative. (Note: The access checking routine knows about the Perl C<stat> operator and file tests, so you shouldn't ever @@ -558,7 +570,7 @@ mailbox buffers to be, and didn't get an answer. (F) The deeply magical "goto subroutine" call can only replace one subroutine call for another. It can't manufacture one out of whole cloth. In general -you should only be calling it out of an AUTOLOAD routine anyway. See +you should be calling it out of only an AUTOLOAD routine anyway. See L<perlfunc/goto>. =item Can't localize a reference @@ -602,16 +614,16 @@ a B<-e> switch. Maybe your /tmp partition is full, or clobbered. =item Can't modify %s in %s (F) You aren't allowed to assign to the item indicated, or otherwise try to -change it, such as with an autoincrement. +change it, such as with an auto-increment. =item Can't modify non-existent substring (P) The internal routine that does assignment to a substr() was handed a NULL. -=item Can't msgrcv to readonly var +=item Can't msgrcv to read-only var -(F) The target of a msgrcv must be modifiable in order to be used as a receive +(F) The target of a msgrcv must be modifiable to be used as a receive buffer. =item Can't open %s: %s @@ -684,7 +696,7 @@ of suidperl. =item Can't take log of %g -(F) Logarithms are only defined on positive real numbers. +(F) Logarithms are defined on only positive real numbers. =item Can't take sqrt of %g @@ -738,7 +750,7 @@ test the type of the reference, if need be. (W) In an ordinary expression, backslash is a unary operator that creates a reference to its argument. The use of backslash to indicate a backreference -to a matched substring is only valid as part of a regular expression pattern. +to a matched substring is valid only as part of a regular expression pattern. Trying to do this in ordinary Perl code produces a value that prints out looking like SCALAR(0xdecaf). Use the $1 form instead. @@ -755,7 +767,7 @@ be a defined value. This helps to de-lurk some insidious errors. =item Can't use global %s in "my" (F) You tried to declare a magical variable as a lexical variable. This is -not allowed, because the magic can only be tied to one location (namely +not allowed, because the magic can be tied to only one location (namely the global variable) and it would be incredibly confusing to have variables in your program that looked like magical variables but weren't. @@ -771,7 +783,7 @@ didn't look like an array reference, or anything else subscriptable. (F) The write routine failed for some reason while trying to process a B<-e> switch. Maybe your /tmp partition is full, or clobbered. -=item Can't x= to readonly value +=item Can't x= to read-only value (F) You tried to repeat a constant value (often the undefined value) with an assignment operator, which implies modifying the value itself. @@ -830,7 +842,12 @@ case it indicates something else. (W) You probably said %hash{$key} when you meant $hash{$key} or @hash{@keys}. On the other hand, maybe you just meant %hash and got carried away. -=item Do you need to predeclare %s? +=item Died. + +(F) You passed die() an empty string (the equivalent of C<die "">) or +you called it with no args and both C<$@> and C<$_> were empty. + +=item Do you need to pre-declare %s? (S) This is an educated guess made in conjunction with the message "%s found where operator expected". It often means a subroutine or module @@ -869,7 +886,7 @@ The interpreter is immediately exited. =item Error converting file specification %s -(F) An error peculiar to VMS. Since Perl may have to deal with file +(F) An error peculiar to VMS. Because Perl may have to deal with file specifications in either VMS or Unix syntax, it converts them to a single form when it must operate on them directly. Either you've passed an invalid file specification to Perl, or you've found a @@ -912,20 +929,20 @@ PDP-11 or something? You need to do an open() or a socket() call, or call a constructor from the FileHandle package. -=item Filehandle %s opened only for input +=item Filehandle %s opened for only input (W) 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 "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If -you only intended to write the file, use "E<gt>" or "E<gt>E<gt>". See +you intended only to write the file, use "E<gt>" or "E<gt>E<gt>". See L<perlfunc/open>. -=item Filehandle only opened for input +=item Filehandle opened for only input (W) 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 "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If -you only intended to write the file, use "E<gt>" or "E<gt>E<gt>". See +you intended only to write the file, use "E<gt>" or "E<gt>E<gt>". See L<perlfunc/open>. =item Final $ should be \$ or $name @@ -1022,8 +1039,8 @@ is now heavily deprecated. (W) A warning peculiar to VMS. A logical name was encountered when preparing to iterate over %ENV which violates the syntactic rules governing logical -names. Since it cannot be translated normally, it is skipped, and will not -appear in %ENV. This may be a benign occurence, as some software packages +names. Because it cannot be translated normally, it is skipped, and will not +appear in %ENV. This may be a benign occurrence, as some software packages might directly modify logical name tables and introduce non-standard names, or it may indicate that a logical name table has been corrupted. @@ -1084,7 +1101,7 @@ architecture. On a 32-bit architecture the largest octal literal is =item Internal inconsistency in tracking vforks (S) A warning peculiar to VMS. Perl keeps track of the number -of times you've called C<fork> and C<exec>, in order to determine +of times you've called C<fork> and C<exec>, to determine whether the current call to C<exec> should affect the current script or a subprocess (see L<perlvms/exec>). Somehow, this count has become scrambled, so Perl is making a guess and treating @@ -1192,7 +1209,7 @@ the previous line just because you saw this message. =item Modification of a read-only value attempted (F) You tried, directly or indirectly, to change the value of a -constant. You didn't, of course, try "2 = 1", since the compiler +constant. You didn't, of course, try "2 = 1", because the compiler catches that. But an easy way to do the same thing is: sub mod { $_[0] = 1 } @@ -1238,10 +1255,10 @@ that is less than 0. This is difficult to imagine. =item nested *?+ in regexp -(F) You can't quantify a quantifier without intervening parens. So +(F) You can't quantify a quantifier without intervening parentheses. So things like ** or +* or ?* are illegal. -Note, however, that the minimal matching quantifiers, *?, +? and ?? appear +Note, however, that the minimal matching quantifiers, C<*?>, C<+?>, and C<??> appear to be nested quantifiers, but aren't. See L<perlre>. =item No #! line @@ -1284,7 +1301,7 @@ right. =item No dbm on this machine (P) This is counted as an internal error, because every machine should -supply dbm nowadays, since Perl comes with SDBM. See L<SDBM_File>. +supply dbm nowadays, because Perl comes with SDBM. See L<SDBM_File>. =item No DBsub routine @@ -1414,7 +1431,7 @@ See L<perlform>. =item Null filename used -(F) You can't require the null filename, especially since on many machines +(F) You can't require the null filename, especially because on many machines that means the current directory! See L<perlfunc/require>. =item Null picture in formline @@ -1433,7 +1450,7 @@ supplied it an uninitialized value. See L<perlform>. =item NULL regexp argument -(P) The internal pattern matching routines blew it bigtime. +(P) The internal pattern matching routines blew it big time. =item NULL regexp parameter @@ -1442,7 +1459,7 @@ supplied it an uninitialized value. See L<perlform>. =item Odd number of elements in hash list (S) You specified an odd number of elements to a hash list, which is odd, -since hash lists come in key/value pairs. +because hash lists come in key/value pairs. =item Offset outside string @@ -1554,7 +1571,7 @@ it wasn't a block context. =item panic: leave_scope clearsv -(P) A writable lexical variable became readonly somehow within the scope. +(P) A writable lexical variable became read-only somehow within the scope. =item panic: leave_scope inconsistency @@ -1640,7 +1657,7 @@ was string. (P) The lexer got into a bad state while processing a case modifier. -=item Parens missing around "%s" list +=item Pareneses missing around "%s" list (W) You said something like @@ -1675,7 +1692,7 @@ the BSD version, which takes a pid. =item Possible attempt to put comments in qw() list -(W) You probably wrote somthing like this: +(W) You probably wrote something like this: qw( a # a comment b # another comment @@ -1689,7 +1706,7 @@ when you should have written this: =item Possible attempt to separate words with commas -(W) You probably wrote somthing like this: +(W) You probably wrote something like this: qw( a, b, c ); @@ -1716,7 +1733,7 @@ is now misinterpreted as because of the strict regularization of Perl 5's grammar into unary and list operators. (The old open was a little of both.) You must put -parens around the filehandle, or use the new "or" operator instead of "||". +parentheses around the filehandle, or use the new "or" operator instead of "||". =item print on closed filehandle %s @@ -1738,7 +1755,7 @@ last argument of the previous construct, for example: =item Prototype mismatch: (%s) vs (%s) -(S) The subroutine being defined had a predeclared (forward) declaration +(S) The subroutine being defined had a pre-declared (forward) declaration with a different function prototype. =item Read on closed filehandle E<lt>%sE<gt> @@ -1803,10 +1820,10 @@ an array. Generally it's better to ask for a scalar value (indicated by $). The difference is that C<$foo[&bar]> always behaves like a scalar, both when assigning to it and when evaluating its argument, while C<@foo[&bar]> behaves like a list when you assign to it, and provides a list context to its -subscript, which can do weird things if you're only expecting one subscript. +subscript, which can do weird things if you're expecting only one subscript. On the other hand, if you were actually hoping to treat the array -element as a list, you need to look into how references work, since +element as a list, you need to look into how references work, because Perl will not magically convert between scalars and lists for you. See L<perlref>. @@ -1851,7 +1868,7 @@ Check your logic flow. =item Sequence (?#... not terminated (F) A regular expression comment must be terminated by a closing -parenthesis. Embedded parens aren't allowed. See L<perlre>. +parenthesis. Embedded parentheses aren't allowed. See L<perlre>. =item Sequence (?%s...) not implemented @@ -1963,7 +1980,7 @@ by itself. (P) The substitution was looping infinitely. (Obviously, a substitution shouldn't iterate more times than there are characters of input, which is what happened.) See the discussion of substitution in -L<perlop/"Quote and Quotelike Operators">. +L<perlop/"Quote and Quote-like Operators">. =item Substitution pattern not terminated @@ -2001,7 +2018,7 @@ Often there will be another error message associated with the syntax error giving more information. (Sometimes it helps to turn on B<-w>.) The error message itself often tells you where it was in the line when it decided to give up. Sometimes the actual error is several tokens -before this, since Perl is good at understanding random input. +before this, because Perl is good at understanding random input. Occasionally the line number may be misleading, and once in a blue moon the only way to figure out what's triggering the error is to call C<perl -c> repeatedly, chopping away half the program each time to see @@ -2015,7 +2032,7 @@ into Perl yourself. =item System V IPC is not implemented on this machine -(F) You tried to do something with a function beginning with "sem", "shm" +(F) You tried to do something with a function beginning with "sem", "shm", or "msg". See L<perlfunc/semctl>, for example. =item Syswrite on closed filehandle @@ -2036,7 +2053,7 @@ open. Check your logic. See also L<perlfunc/-X>. =item That use of $[ is unsupported (F) Assignment to C<$[> is now strictly circumscribed, and interpreted as -a compiler directive. You may only say one of +a compiler directive. You may say only one of $[ = 0; $[ = 1; @@ -2087,7 +2104,7 @@ into Perl yourself. =item Too many args to syscall -(F) Perl only supports a maximum of 14 args to syscall(). +(F) Perl supports a maximum of only 14 args to syscall(). =item Too many arguments for %s @@ -2122,7 +2139,7 @@ certain type. Arrays must be @NAME or C<@{EXPR}>. Hashes must be =item umask: argument is missing initial 0 -(W) A umask of 222 is incorrect. It should be 0222, since octal literals +(W) A umask of 222 is incorrect. It should be 0222, because octal literals always start with 0 in Perl, as in C. =item Unable to create sub named "%s" @@ -2186,13 +2203,13 @@ representative, who probably put it there in the first place. =item Unknown BYTEORDER -(F) There are no byteswapping functions for a machine with this byte order. +(F) There are no byte-swapping functions for a machine with this byte order. =item unmatched () in regexp (F) Unbackslashed parentheses must always be balanced in regular expressions. If you're a vi user, the % key is valuable for finding -the matching paren. See L<perlre>. +the matching parenthesis. See L<perlre>. =item Unmatched right bracket @@ -2263,15 +2280,15 @@ Use an explicit printf() or sprintf() instead. =item Use of $* is deprecated -(D) This variable magically turned on multiline pattern matching, both for +(D) This variable magically turned on multi-line pattern matching, both for you and for any luckless subroutine that you happen to call. You should use the new C<//m> and C<//s> modifiers now to do that without the dangerous action-at-a-distance effects of C<$*>. =item Use of %s in printf format not supported -(F) You attempted to use a feature of printf that is accessible only -from C. This usually means there's a better way to do it in Perl. +(F) You attempted to use a feature of printf that is accessible from +only C. This usually means there's a better way to do it in Perl. =item Use of %s is deprecated @@ -2346,12 +2363,17 @@ on the front of your variable. of Perl. Check the E<lt>#!E<gt> line, or manually feed your script into Perl yourself. +=item Warning: something's wrong. + +(W) You passed warn() an empty string (the equivalent of C<warn "">) or +you called it with no args and C<$_> was empty. + =item Warning: unable to close filehandle %s properly. (S) The implicit close() done by an open() got an error indication on the -close(). This usually indicates your filesystem ran out of disk space. +close(). This usually indicates your file system ran out of disk space. -=item Warning: Use of "%s" without parens is ambiguous +=item Warning: Use of "%s" without parentheses is ambiguous (S) You wrote a unary operator followed by something that looks like a binary operator that could also have been interpreted as a term or @@ -2368,7 +2390,7 @@ but in actual fact, you got rand(+5); -So put in parens to say what you really mean. +So put in parentheses to say what you really mean. =item Write on closed filehandle @@ -2401,7 +2423,7 @@ Use a filename instead. =item YOU HAVEN'T DISABLED SET-ID SCRIPTS IN THE KERNEL YET! -(F) And you probably never will, since you probably don't have the +(F) And you probably never will, because you probably don't have the sources to your kernel, and your vendor probably doesn't give a rip about what you want. Your best bet is to use the wrapsuid script in the eg directory to put a setuid C wrapper around your script. @@ -2422,7 +2444,7 @@ See L<perlfunc/getsockopt>. =item \1 better written as $1 (W) Outside of patterns, backreferences live on as variables. The use -of backslashes is grandfathered on the righthand side of a +of backslashes is grandfathered on the right-hand side of a substitution, but stylistically it's better to use the variable form because other Perl programmers will expect it, and it works better if there are more than 9 backreferences. @@ -2451,7 +2473,7 @@ streams, such as =item Got an error from DosAllocMem: (P) An error peculiar to OS/2. Most probably you use an obsolete version -of perl, and should not happen anyway. +of perl, and this should not happen anyway. =item Malformed PERLLIB_PREFIX |