diff options
| -rw-r--r-- | wrapper.c | 16 |
1 files changed, 15 insertions, 1 deletions
@@ -172,8 +172,22 @@ void *xcalloc(size_t nmemb, size_t size) * 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in * the absence of bugs, large chunks can result in bad latencies when * you decide to kill the process. + * + * We pick 8 MiB as our default, but if the platform defines SSIZE_MAX + * that is smaller than that, clip it to SSIZE_MAX, as a call to + * read(2) or write(2) larger than that is allowed to fail. As the last + * resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value" + * to override this, if the definition of SSIZE_MAX given by the platform + * is broken. */ -#define MAX_IO_SIZE (8*1024*1024) +#ifndef MAX_IO_SIZE +# define MAX_IO_SIZE_DEFAULT (8*1024*1024) +# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT) +# define MAX_IO_SIZE SSIZE_MAX +# else +# define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT +# endif +#endif /* * xread() is the same a read(), but it automatically restarts read() |