#include <limits.h>
+#ifndef CHAR_BIT
+# define CHAR_BIT 8
+#endif
+
+/* The extra casts work around common compiler bugs. */
+#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
+/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
+ It is necessary at least when t == time_t. */
+#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
+ ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
+#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
+
+#ifndef INT_MAX
+# define INT_MAX TYPE_MAXIMUM (int)
+#endif
+
/* We don't pass an nbytes count > SSIZE_MAX to write() - POSIX says the
effect would be implementation-defined. Also we don't pass an nbytes
count > INT_MAX but <= SSIZE_MAX to write() - this triggers a bug in
size_t
safe_write (int fd, const void *buf, size_t count)
{
- size_t total_written = 0;
+ size_t nbytes_to_write = count;
+ ssize_t result;
+
+ /* Limit the number of bytes to write, to avoid running into unspecified
+ behaviour. But keep the file pointer block aligned when doing so.
+ Note that in this case we don't need to call write() multiple times here,
+ because the caller is prepared to partial results. */
+ if (nbytes_to_write > MAX_BYTES_TO_READ)
+ nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
- if (count > 0)
+ do
{
- const char *ptr = (const char *) buf;
- do
- {
- size_t nbytes_to_write = count;
- ssize_t result;
-
- /* Limit the number of bytes to write in one round, to avoid running
- into unspecified behaviour. But keep the file pointer block
- aligned when doing so. */
- if (nbytes_to_write > MAX_BYTES_TO_READ)
- nbytes_to_write = MAX_BYTES_TO_READ & ~8191;
-
- result = write (fd, ptr, nbytes_to_write);
- if (result < 0)
- {
+ result = write (fd, buf, nbytes_to_write);
+ }
#ifdef EINTR
- if (errno == EINTR)
- continue;
+ while (result < 0 && errno == EINTR);
+#else
+ while (0);
#endif
- return result;
- }
- total_written += result;
- ptr += result;
- count -= result;
- }
- while (count > 0);
- }
- return total_written;
+ return (size_t) result;
}