Warning: Redefining fopen64 with std::fopen

[jakirkham]

Am seeing the following warning when building xgboost on Linux and macOS. It seems to be pointing to dmlc-core. So am raising here. Appears there is an issue where fopen64 is being redefined with std::fopen. Build logs linked below as well in case they are of interest.

/home/conda/feedstock_root/build_artifacts/xgboost_1571964986924/work/dmlc-core/src/build_config.cc:14:6: warning: #warning "Redefining fopen64 with std::fopen" [-Wcpp]
     #warning "Redefining fopen64 with std::fopen"
      ^~~~~~~

ref: https://dev.azure.com/conda-forge/feedstock-builds/_build/results?buildId=84089

[hcho3]

@jakirkham This is expected, since you are using 64-bit systems. Some 32-bit systems define fopen64() and fopen() separately, whereas in 64-bit systems, fopen64() is an alias of fopen().

[leezu]

@hcho3 why then print the warning? If this is standard practice, no need to print an extra warning

dmlc-core/src/build_config.cc

Lines 10 to 16 in c8f7f9c

	#ifdef DMLC_EMIT_FOPEN64_REDEFINE_WARNING
	#ifdef _MSC_VER
	#pragma message(": warning : Redefining fopen64 with std::fopen")
	#else
	#warning "Redefining fopen64 with std::fopen"
	#endif
	#endif // DMLC_EMIT_FOPEN64_REDEFINE_WARNING

If not, why do it?

[hcho3]

@leezu I didn't add the warning. The warning was added by #432.

[leezu]

Ok. I suggest to remove the warning: #598