Brandon Streiff created THRIFT-1666:
---------------------------------------
Summary: htonll usage in TBinaryProtocol.tcc generates warning
with MSVC2010
Key: THRIFT-1666
URL: https://issues.apache.org/jira/browse/THRIFT-1666
Project: Thrift
Issue Type: Bug
Components: C++ - Library
Affects Versions: 0.8
Environment: Microsoft Visual Studio 10.0 (2010).
Reporter: Brandon Streiff
Priority: Trivial
When using the Thrift library I get warnings like the following:
{code}thrift\protocol\TBinaryProtocol.tcc(161): warning C4244: 'argument' :
conversion from 'const int64_t' to 'u_long', possible loss of data{code}
This is because TBinaryProtocol.tcc uses {{htonll}} on an incoming {{const
int64_t}} parameter to perform byteswapping, and in TProtocol.h {{htonll}} gets
defined like so:
{code}# define htonll(n) ( (((uint64_t)htonl(n)) << 32) + htonl(n >> 32)
){code}
[ntohl() takes a u_long
parameter|http://msdn.microsoft.com/en-us/library/windows/desktop/ms740069%28v=vs.85%29.aspx],
so MSVC warns when passing in a uint64_t parameter because it truncates. This
could have been fixed by casting the input parameters, but there's also a nice
handy
[_byteswap_uint64()|http://msdn.microsoft.com/en-us/library/a3140177%28v=vs.100%29.aspx]
function in the MSVC CRT that we can use without all of the shifting that
calling ntohl twice requires.
Patch follows:
{code}
--- a\lib\cpp\src\protocol\TProtocol.h 31 Jul 2012 9:18:02 AM
+++ b\lib\cpp\src\protocol\TProtocol.h 31 Jul 2012 9:19:48 AM
@@ -127,140 +127,143 @@
# define letohll(n) (n)
# if defined(__GNUC__) && defined(__GLIBC__)
# include <byteswap.h>
# define ntohll(n) bswap_64(n)
# define htonll(n) bswap_64(n)
-# else /* GNUC & GLIBC */
+# elif defined(_MSC_VER) /* Microsoft Visual C++ */
+# define ntohll(n) ( _byteswap_uint64((uint64_t)n) )
+# define htonll(n) ( _byteswap_uint64((uint64_t)n) )
+# else /* Not GNUC/GLIBC or MSVC */
# define ntohll(n) ( (((uint64_t)ntohl(n)) << 32) + ntohl(n >> 32) )
# define htonll(n) ( (((uint64_t)htonl(n)) << 32) + htonl(n >> 32) )
-# endif /* GNUC & GLIBC */
+# endif /* GNUC/GLIBC or MSVC or something else */
#else /* __BYTE_ORDER */
# error "Can't define htonll or ntohll!"
#endif
/**
{code}
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
