X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlfunc.pod;h=08c406c0cdd787a52aa5f47380d255a1e810fc40;hb=c1effa61278e47c916466883d74905b04fedc388;hp=884644eb2224a7c5ea067d1d59ffd291bea45161;hpb=1cb246e8dcbc92bfdff3156b4963ab3a06f97534;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlfunc.pod b/pod/perlfunc.pod index 884644e..08c406c 100644 --- a/pod/perlfunc.pod +++ b/pod/perlfunc.pod @@ -1234,6 +1234,10 @@ lookup: delete $ref->[$x][$y][$index]; delete @{$ref->[$x][$y]}[$index1, $index2, @moreindices]; +The C construct can also be used to localize the deletion +of array/hash elements to the current block. +See L. + =item die LIST X X X X X<$@> X @@ -1271,14 +1275,14 @@ produce, respectively See also exit(), warn(), and the Carp module. -If LIST is empty and C<$@> already contains a value (typically from a +If the output is empty and C<$@> already contains a value (typically from a previous eval) that value is reused after appending C<"\t...propagated">. This is useful for propagating exceptions: eval { ... }; die unless $@ =~ /Expected exception/; -If LIST is empty and C<$@> contains an object reference that has a +If the output is empty and C<$@> contains an object reference that has a C method, that method will be called with additional file and line number parameters. The return value replaces the value in C<$@>. i.e. as if C<< $@ = eval { $@->PROPAGATE(__FILE__, __LINE__) }; >> @@ -2631,11 +2635,13 @@ the super-user). This is a useful way to check that a child process is alive (even if only as a zombie) and hasn't changed its UID. See L for notes on the portability of this construct. -Unlike in the shell, if SIGNAL is negative, it kills -process groups instead of processes. (On System V, a negative I -number will also kill process groups, but that's not portable.) That -means you usually want to use positive not negative signals. You may also -use a signal name in quotes. +Unlike in the shell, if SIGNAL is negative, it kills process groups instead +of processes. That means you usually want to use positive not negative signals. +You may also use a signal name in quotes. + +The behavior of kill when a I number is zero or negative depends on +the operating system. For example, on POSIX-conforming systems, zero will +signal the current process group and -1 will signal all processes. See L for more details. @@ -2734,6 +2740,10 @@ block, file, or eval. If more than one value is listed, the list must be placed in parentheses. See L for details, including issues with tied arrays and hashes. +The C construct can also be used to localize the deletion +of array/hash elements to the current block. +See L. + =item localtime EXPR X X @@ -4073,8 +4083,6 @@ The same template may generally also be used in unpack(). =item package NAMESPACE X X X -=item package - Declares the compilation unit as being in the given namespace. The scope of the package declaration is from the declaration itself through the end of the enclosing block, file, or eval (the same as the C operator). @@ -5463,9 +5471,7 @@ Splits the string EXPR into a list of strings and returns that list. By default, empty leading fields are preserved, and empty trailing ones are deleted. (If all fields are empty, they are considered to be trailing.) -In scalar context, returns the number of fields found and splits into -the C<@_> array. Use of split in scalar context is deprecated, however, -because it clobbers your subroutine arguments. +In scalar context, returns the number of fields found. If EXPR is omitted, splits the C<$_> string. If PATTERN is also omitted, splits on whitespace (after skipping any leading whitespace). Anything @@ -6464,6 +6470,9 @@ C, as described in L. Return value of -1 indicates a failure to start the program or an error of the wait(2) system call (inspect $! for the reason). +If you'd like to make C (and many other bits of Perl) die on error, +have a look at the L pragma. + Like C, C allows you to lie to a program about its name if you use the C syntax. Again, see L. @@ -6476,8 +6485,8 @@ value. system(@args) == 0 or die "system @args failed: $?" -You can check all the failure possibilities by inspecting -C<$?> like this: +If you'd like to manually inspect C's failure, you can check all +possible failure modes by inspecting C<$?> like this: if ($? == -1) { print "failed to execute: $!\n"; @@ -6947,6 +6956,9 @@ Cing library modules that won't work with older versions of Perl. Also, if the specified perl version is greater than or equal to 5.9.5, C will also load the C pragma and enable all features available in the requested version. See L. +Similarly, if the specified perl version is greater than or equal to +5.11.0, strictures are enabled lexically as with C (except +that the F file is not actually loaded). The C forces the C and C to happen at compile time. The C makes sure the module is loaded into memory if it hasn't been @@ -7380,7 +7392,7 @@ Prints the value of LIST to STDERR. If the last element of LIST does not end in a newline, it appends the same file/line number text as C does. -If LIST is empty and C<$@> already contains a value (typically from a +If the output is empty and C<$@> already contains a value (typically from a previous eval) that value is used after appending C<"\t...caught"> to C<$@>. This is useful for staying almost, but not entirely similar to C.