gpsd @3.11: driver_rtcm2.c:125:2: error: #error Unknown endianness!

[ryandesign (Ryan Carsten Schmidt)]

gpsd @3.5_4 is installed on my PowerBook G4 running Mac OS X 10.5 Leopard, but I cannot upgrade it to version @3.11_0 because:

/usr/bin/gcc-4.2 -arch ppc -o driver_rtcm2.os -c -Os -arch ppc -D_GNU_SOURCE -Wextra -Wall -Wno-uninitialized -Wno-missing-field-initializers -Wcast-align -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wpointer-arith -Wreturn-type -pthread -Wmissing-prototypes -Wmissing-declarations -O2 -fPIC driver_rtcm2.c
driver_rtcm2.c:125:2: error: #error Unknown endianness!
scons: *** [driver_rtcm2.os] Error 1
scons: building terminated because of errors.

[udbraumann]

Though driver_rtcm2.c states in a comment that in case of such trouble the inclusion of endian.h might be considered, as I found there is no endian.h I instead have used gcc49 for building:

$ sudo port install gpsd configure.compiler=macports-gcc-4.9
--->  Computing dependencies for gpsd
--->  Fetching archive for gpsd
--->  Attempting to fetch gpsd-3.11_0.darwin_9.ppc.tbz2 from http://nue.de.packages.macports.org/macports/packages/gpsd
--->  Attempting to fetch gpsd-3.11_0.darwin_9.ppc.tbz2 from http://lil.fr.packages.macports.org/gpsd
--->  Attempting to fetch gpsd-3.11_0.darwin_9.ppc.tbz2 from http://mse.uk.packages.macports.org/sites/packages.macports.org/gpsd
--->  Fetching distfiles for gpsd
--->  Verifying checksums for gpsd
--->  Extracting gpsd
--->  Applying patches to gpsd
--->  Configuring gpsd
--->  Building gpsd
--->  Staging gpsd into destroot
--->  Installing gpsd @3.11_0
--->  Activating gpsd @3.11_0
--->  Cleaning gpsd
--->  Updating database of binaries
--->  Scanning binaries for linking errors

Hope this will not give problems at runtime when linked with libraries having built with Xcode's gcc42.

[udbraumann]

Cc Me!

[ryandesign (Ryan Carsten Schmidt)]

I don't recommend using a GCC port to build ports like gpsd that don't already call for it.

OS X's endian.h is located in /usr/include/machine. gpsd knows to look there for it.

[ryandesign (Ryan Carsten Schmidt)]

I fixed the problem in r135710. I'll report it to the developer of gpsd.

[ryandesign (Ryan Carsten Schmidt)]

I may as well reproduce here what I sent to the developer, in case anyone is interested:

---

The problem is that on 10.5 only the following are defined:

$ cpp -E -dM < /dev/null | grep -E '(BYTE|ENDIAN)'
#define __BIG_ENDIAN__ 1
#define _BIG_ENDIAN 1

That's on a PowerPC Mac; on an Intel Mac, presumably __LITTLE_ENDIAN__ and _LITTLE_ENDIAN would both be defined to 1.

This runs afoul of the code in gpsd's driver_rtcm2.c which first does this:

/*
* BSD uses _BYTE_ORDER, and Linux uses __BYTE_ORDER.
*/
#if !defined( __BYTE_ORDER) && defined(_BYTE_ORDER)
#define __BYTE_ORDER _BYTE_ORDER
#endif
#if !defined( __BIG_ENDIAN) && defined(_BIG_ENDIAN)
#define __BIG_ENDIAN _BIG_ENDIAN
#endif
#if !defined( __LITTLE_ENDIAN) && defined(_LITTLE_ENDIAN)
#define __LITTLE_ENDIAN _LITTLE_ENDIAN
#endif

And then does this:

/*
* Darwin (Mac OS X) uses special defines.
*/
#if !defined( __BYTE_ORDER) && defined(__DARWIN_BYTE_ORDER)
#define __BYTE_ORDER __DARWIN_BYTE_ORDER
#endif
#if !defined( __BIG_ENDIAN) && defined(__DARWIN_BIG_ENDIAN)
#define __BIG_ENDIAN __DARWIN_BIG_ENDIAN
#endif
#if !defined( __LITTLE_ENDIAN) && defined(__DARWIN_LITTLE_ENDIAN)
#define __LITTLE_ENDIAN __DARWIN_LITTLE_ENDIAN
#endif

On 10.5, in the first block, on PowerPC, __BIG_ENDIAN gets set to _BIG_ENDIAN, i.e. 1 (or on Intel, __LITTLE_ENDIAN gets set to _LITTLE_ENDIAN, i.e. 1), and 1 doesn't match either of the possible values of __BYTE_ORDER == __DARWIN_BYTE_ORDER (which is either __DARWIN_BIG_ENDIAN == 4321 or __DARWIN_LITTLE_ENDIAN == 1234), which is where the error trips:

#if __BYTE_ORDER == __BIG_ENDIAN
#define WORDS_BIGENDIAN 1
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#undef WORDS_BIGENDIAN
#else
#error Unknown endianness!
#endif /* __BYTE_ORDER */

Assuming the BSD block is correct for BSD, the solution I propose is to reverse the order of these two blocks, putting the Darwin block before the BSD one. This allows the build to succeed on 10.5 at least.