Sysconf And _SC_LEVEL1_DCACHE_LINESIZE Returns 0?

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I’m working on GCC112, which is POWER System S822 (Power8) machine running CentOS 7 machine (https://gcc.gnu.org/wiki/CompileFarm):

$ cat /etc/CentOS-release
CentOS Linux release 7.3.1611 (AltArch)

I’m trying to determine L1 data cache size. When the following code runs it returns 0, the man pages state -1 is an error, so I think its claiming to succeed.

cacheLineSize = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);

GCC119, which is also a S822 Power8 running AIX, returns 128.

Does anyone know what I might be doing wrong under Cent? Or maybe, how can I retrieve the L1 data cache line size?