writev: update comment on preserving errno

Studying malloc implementations for a while, it's completely
reasonable for "free" to alter errno when making syscalls
to release/compact memory.

1 files changed, 1 insertions, 2 deletions

diff --git a/ext/kgio/writev.c b/ext/kgio/writev.c
index 027cdb5..d3ec53e 100644
--- a/ext/kgio/writev.c
+++ b/ext/kgio/writev.c
@@ -90,8 +90,7 @@ static ssize_t custom_writev(int fd, const struct iovec *vec, int iov_cnt, size_
 
         result = write(fd, buf, total_len);
 
-        /* well, it seems that `free` could not change errno
-         * but lets save it anyway */
+        /* free() may alter errno */
         i = errno;
         free(buf);
         errno = i;