From 3b9075344f0b151a4fd8e4a0fda25962ff0b9a50 Mon Sep 17 00:00:00 2001
From: Jeremy Lakeman <Jeremy.Lakeman@gmail.com>
Date: Fri, 31 Oct 2014 13:44:20 +1030
Subject: [PATCH] Allow write to return less bytes than we asked for, or zero

---
 tfw_createfile.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/tfw_createfile.c b/tfw_createfile.c
index 1b6bf9a4..77f069b1 100644
--- a/tfw_createfile.c
+++ b/tfw_createfile.c
@@ -114,7 +114,16 @@ int main(int argc, char **argv)
     unsigned remain = size - offset - 1;
     if (remain > sizeof buf)
       remain = sizeof buf;
-    assert(fwrite(buf, remain, 1, stdout)==remain);
+    
+    {
+      size_t off=0;
+      while(off<remain){
+	ssize_t wrote = fwrite(buf+off, 1, remain - off, stdout);
+	if (wrote<0)
+	  fatal("write error: %s [errno=%d]", strerror(errno), errno);
+	off+=wrote;
+      }
+    }
     assert(fputc('\n', stdout)!=EOF);
     offset += remain + 1;
     if (bounce <= n || bounce >= bouncemax)