[commit: ghc] master: base: fdReady(): Ensure and doc that return values are always -1/0/1 (03009aa)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/03009aa70a099867331afb9876333c687454c5d5/ghc

>---------------------------------------------------------------

commit 03009aa70a099867331afb9876333c687454c5d5
Author: Niklas Hambüchen <mail at nh2.me>
Date:   Wed Sep 27 15:29:06 2017 -0400

    base: fdReady(): Ensure and doc that return values are always -1/0/1
    
    Reviewers: bgamari, austin, hvr, Phyx
    
    Reviewed By: Phyx
    
    Subscribers: Phyx, rwbarton, thomie
    
    Differential Revision: https://phabricator.haskell.org/D4010


>---------------------------------------------------------------

03009aa70a099867331afb9876333c687454c5d5
 libraries/base/cbits/inputReady.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libraries/base/cbits/inputReady.c b/libraries/base/cbits/inputReady.c
index 21ad36d..30327ba 100644
--- a/libraries/base/cbits/inputReady.c
+++ b/libraries/base/cbits/inputReady.c
@@ -40,6 +40,10 @@
  *
  * This function blocks until either `msecs` have passed, or input is
  * available.
+ *
+ * Returns:
+ *   1 => Input ready, 0 => not ready, -1 => error
+ * On error, sets `errno`.
  */
 int
 fdReady(int fd, int write, int msecs, int isSock)
@@ -117,8 +121,7 @@ fdReady(int fd, int write, int msecs, int isSock)
             }
         }
 
-        /* 1 => Input ready, 0 => not ready, -1 => error */
-        return (ready);
+        return (ready > 0);
     } else {
         DWORD rc;
         HANDLE hFile = (HANDLE)_get_osfhandle(fd);