From: Christopher Dykes <cdykes@fb.com>
Date: Thu, 25 Aug 2016 21:52:59 +0000 (-0700)
Subject: lseek returns the new offset, not 0
X-Git-Tag: v2016.08.29.00~8
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ff5c9335246b6b02bbe9435744722415423f348d;p=folly.git

lseek returns the new offset, not 0

Summary:
With how this was written it would fail if the call to `lseek` failed, or if it succeeded, unless it was setting the length to 0, in which case it would succeed.
This makes it work right.

Reviewed By: yfeldblum

Differential Revision: D3773311

fbshipit-source-id: 3dc94502d0c4259f6f2766b4c0903c081d7c36ab
---

diff --git a/folly/portability/Unistd.cpp b/folly/portability/Unistd.cpp
index 27fc7c77..bf598d23 100755
--- a/folly/portability/Unistd.cpp
+++ b/folly/portability/Unistd.cpp
@@ -92,7 +92,7 @@ int fsync(int fd) {
 }
 
 int ftruncate(int fd, off_t len) {
-  if (_lseek(fd, len, SEEK_SET)) {
+  if (_lseek(fd, len, SEEK_SET) == -1) {
     return -1;
   }