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| author | Aaron Crane <arc@cpan.org> | 2017-10-12 13:47:22 +0200 |
|---|---|---|
| committer | Aaron Crane <arc@cpan.org> | 2017-10-21 16:51:21 +0100 |
| commit | 1c1d7d5ba0bc33e7bea0a9aeb2d420fc5a8128ab (patch) | |
| tree | 74492a42f48126a77646de9420baebc6c28041bf /plan9/config_h.sample | |
| parent | 04322328fc4bc2863d0bc74339ed92d33b7eaba7 (diff) | |
| download | perl-1c1d7d5ba0bc33e7bea0a9aeb2d420fc5a8128ab.tar.gz | |
Don't look for a "safe" memcpy()
C89 says that, if you want to copy overlapping memory blocks, you must use
memmove(), and that attempt to copy overlapping memory blocks using memcpy()
yields undefined behaviour. So we should never even attempt to probe for a
system memcpy() implementation that just happens to handle overlapping
memory blocks. In particular, the compiler might compile the probe program
in such a way that Configure thinks overlapping memcpy() works even when it
doesn't.
This has the additional advantage of removing a Configure probe that needs
to execute a target-platform program on the build host.
Diffstat (limited to 'plan9/config_h.sample')
| -rw-r--r-- | plan9/config_h.sample | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/plan9/config_h.sample b/plan9/config_h.sample index 5baf0540b2..98811d493d 100644 --- a/plan9/config_h.sample +++ b/plan9/config_h.sample @@ -2096,14 +2096,6 @@ */ /*#define HAS_SAFE_BCOPY / **/ -/* HAS_SAFE_MEMCPY: - * This symbol, if defined, indicates that the memcpy routine is available - * to copy potentially overlapping memory blocks. If you need to - * copy overlapping memory blocks, you should check HAS_MEMMOVE and - * use memmove() instead, if available. - */ -/*#define HAS_SAFE_MEMCPY / **/ - /* HAS_SANE_MEMCMP: * This symbol, if defined, indicates that the memcmp routine is available * and can be used to compare relative magnitudes of chars with their high |