path: root/git-compat-util.h
diff options
authorShawn O. Pearce <>2007-03-07 01:44:37 (GMT)
committerJunio C Hamano <>2007-03-07 19:15:26 (GMT)
commitdc49cd769b5fa6b7e0114b051c34a849828a7603 (patch)
tree7eafafcd36ab731599da3fb5e59d3f4379c342d3 /git-compat-util.h
parent6777a59fcdfd96b9ca5cba49cb265c6c47de3d02 (diff)
Cast 64 bit off_t to 32 bit size_t
Some systems have sizeof(off_t) == 8 while sizeof(size_t) == 4. This implies that we are able to access and work on files whose maximum length is around 2^63-1 bytes, but we can only malloc or mmap somewhat less than 2^32-1 bytes of memory. On such a system an implicit conversion of off_t to size_t can cause the size_t to wrap, resulting in unexpected and exciting behavior. Right now we are working around all gcc warnings generated by the -Wshorten-64-to-32 option by passing the off_t through xsize_t(). In the future we should make xsize_t on such problematic platforms detect the wrapping and die if such a file is accessed. Signed-off-by: Shawn O. Pearce <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'git-compat-util.h')
1 files changed, 5 insertions, 0 deletions
diff --git a/git-compat-util.h b/git-compat-util.h
index 33b68e4..7534db1 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -258,6 +258,11 @@ static inline ssize_t xwrite(int fd, const void *buf, size_t len)
+static inline size_t xsize_t(off_t len)
+ return (size_t)len;
static inline int has_extension(const char *filename, const char *ext)
size_t len = strlen(filename);