perlfunc.pod grammar fixes

[p5sagit/p5-mst-13.2.git] / pod / perlhack.pod

diff --git a/pod/perlhack.pod b/pod/perlhack.pod
index f90c48b..9dc1053 100644 (file)
--- a/pod/perlhack.pod
+++ b/pod/perlhack.pod
@@ -877,9 +877,9 @@ retrieves the return op from it, and returns it.
 
 =item Exception handing
 
-Perl's exception handing (ie C<die> etc) is built on top of the low-level
+Perl's exception handing (i.e. C<die> etc) is built on top of the low-level
 C<setjmp()>/C<longjmp()> C-library functions. These basically provide a
-way to capture the current PC and SP registers and later restore them; ie
+way to capture the current PC and SP registers and later restore them; i.e.
 a C<longjmp()> continues at the point in code where a previous C<setjmp()>
 was done, with anything further up on the C stack being lost. This is why
 code should always save values using C<SAVE_FOO> rather than in auto
@@ -2468,6 +2468,19 @@ memory usage, so it shouldn't be used in production environments. It also
 converts C<new_SV()> from a macro into a real function, so you can use
 your favourite debugger to discover where those pesky SVs were allocated.
 
+=head2 PERL_MEM_LOG
+
+If compiled with C<-DPERL_MEM_LOG>, all Newx() and Renew() allocations
+and Safefree() in the Perl core go through logging functions, which is
+handy for breakpoint setting.  If also compiled with C<-DPERL_MEM_LOG_STDERR>,
+the allocations and frees are logged to STDERR (or more precisely, to the
+file descriptor 2) in these logging functions, with the calling source code
+file and line number (and C function name, if supported by the C compiler).
+
+This logging is somewhat similar to C<-Dm> but independent of C<-DDEBUGGING>,
+and at a higher level (the C<-Dm> is directly at the point of C<malloc()>,
+while the C<PERL_MEMLOG> is at the level of C<New()>>.
+
 =head2 Profiling
 
 Depending on your platform there are various of profiling Perl.