Round up all string length requests to malloc()/realloc() to the next

multiple of 4/8 bytes [sizeof(size_t)] on the assumption that malloc()
internally will quantise, and so we're going to use space that
otherwise would be wasted. Hopefully this will save realloc()ing.

p4raw-id: //depot/perl@24665

1 files changed, 7 insertions, 0 deletions

diff --git a/perl.h b/perl.h
index bfa632f5a4..aedc918923 100644
--- a/perl.h
+++ b/perl.h
@@ -803,6 +803,13 @@ int usleep(unsigned int);
 
 #define MEM_SIZE Size_t
 
+/* Round all values passed to malloc up, by default to a multiple of
+   sizeof(size_t)
+*/
+#ifndef PERL_STRLEN_ROUNDUP_QUANTUM
+#define PERL_STRLEN_ROUNDUP_QUANTUM Size_t_size
+#endif
+
 #if defined(STANDARD_C) && defined(I_STDDEF)
 #   include <stddef.h>
 #   define STRUCT_OFFSET(s,m)  offsetof(s,m)