File ‘RFCCA/libs/RFCCA.so’:
  Found non-API call to R: ‘STRING_PTR’

Compiled code should not call non-API entry points in R.

See ‘Writing portable packages’ in the ‘Writing R Extensions’ manual,
and section ‘Moving into C API compliance’ for issues with the use of
non-API entry points.
File ‘RFCCA/libs/RFCCA.so’:
  Found non-API call to R: ‘STRING_PTR’

Compiled code should not call non-API entry points in R.

See ‘Writing portable packages’ in the ‘Writing R Extensions’ manual,
and section ‘Moving into C API compliance’ for issues with the use of
non-API entry points.
File ‘RFCCA/libs/RFCCA.so’:
  Found non-API call to R: ‘STRING_PTR’

Compiled code should not call non-API entry points in R.

See ‘Writing portable packages’ in the ‘Writing R Extensions’ manual,
and section ‘Moving into C API compliance’ for issues with the use of
non-API entry points.
File ‘RFCCA/libs/RFCCA.so’:
  Found non-API call to R: ‘STRING_PTR’

Compiled code should not call non-API entry points in R.

See ‘Writing portable packages’ in the ‘Writing R Extensions’ manual,
and section ‘Moving into C API compliance’ for issues with the use of
non-API entry points.
File 'RFCCA/libs/x64/RFCCA.dll':
  Found non-API call to R: 'STRING_PTR'

Compiled code should not call non-API entry points in R.

See 'Writing portable packages' in the 'Writing R Extensions' manual,
and section 'Moving into C API compliance' for issues with the use of
non-API entry points.