Fix for RT #52552.

[p5sagit/p5-mst-13.2.git] / handy.h

diff --git a/handy.h b/handy.h
index 26a41a5..d390667 100644 (file)
--- a/handy.h
+++ b/handy.h
@@ -48,6 +48,15 @@ Null SV pointer. (No longer available when C<PERL_CORE> is defined.)
 #define TRUE (1)
 #define FALSE (0)
 
+/* The MUTABLE_*() macros cast pointers to the types shown, in such a way
+ * (compiler permitting) that casting away const-ness will give a warning;
+ * e.g.:
+ *
+ * const SV *sv = ...;
+ * AV *av1 = (AV*)sv;        <== BAD:  the const has been silently cast away
+ * AV *av2 = MUTABLE_AV(sv); <== GOOD: it may warn
+ */
+
 #if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
 #  define MUTABLE_PTR(p) ({ void *_p = (p); _p; })
 #else
@@ -752,7 +761,7 @@ PoisonWith(0xEF) for catching access to freed memory.
  * which more importantly get the immediate calling environment (file and
  * line number, and C function name if available) passed in.  This info can
  * then be used for logging the calls, for which one gets a sample
- * implementation if PERL_MEM_LOG_STDERR is defined.
+ * implementation unless -DPERL_MEM_LOG_NOIMPL is also defined.
  *
  * Known problems:
  * - all memory allocs do not get logged, only those
@@ -774,6 +783,8 @@ PoisonWith(0xEF) for catching access to freed memory.
  *   (keyed by the allocation address?), and maintain that
  *   through reallocs and frees, but how to do that without
  *   any News() happening...?
+ * - lots of -Ddefines to get useful/controllable output
+ * - lots of ENV reads
  */
 
 PERL_EXPORT_C Malloc_t Perl_mem_log_alloc(const UV n, const UV typesize, const char *type_name, Malloc_t newalloc, const char *filename, const int linenumber, const char *funcname);
@@ -783,7 +794,7 @@ PERL_EXPORT_C Malloc_t Perl_mem_log_realloc(const UV n, const UV typesize, const
 PERL_EXPORT_C Malloc_t Perl_mem_log_free(Malloc_t oldalloc, const char *filename, const int linenumber, const char *funcname);
 
 # ifdef PERL_CORE
-#  ifdef PERL_MEM_LOG_STDERR
+#  ifndef PERL_MEM_LOG_NOIMPL
 enum mem_log_type {
   MLT_ALLOC,
   MLT_REALLOC,