diff -ur root-6.22.00.orig/io/io/src/RRawFileUnix.cxx root-6.22.00/io/io/src/RRawFileUnix.cxx

--- root-6.22.00.orig/io/io/src/RRawFileUnix.cxx	2020-06-14 17:51:48.000000000 +0200

+++ root-6.22.00/io/io/src/RRawFileUnix.cxx	2020-07-02 09:02:48.202677798 +0200

@@ -9,6 +9,8 @@

  * For the list of contributors see $ROOTSYS/README/CREDITS.             *

  *************************************************************************/

+#include "ROOT/RConfig.hxx"

+

 #include "ROOT/RRawFileUnix.hxx"

 #include "ROOT/RMakeUnique.hxx"

@@ -47,8 +49,13 @@

 std::uint64_t ROOT::Internal::RRawFileUnix::GetSizeImpl()

 {

+#ifdef R__SEEK64

+   struct stat64 info;

+   int res = fstat64(fFileDes, &info;;

+#else

    struct stat info;

    int res = fstat(fFileDes, &info;;

+#endif

    if (res != 0)

       throw std::runtime_error("Cannot call fstat on '" + fUrl + "', error: " + std::string(strerror(errno)));

    return info.st_size;

@@ -68,7 +75,11 @@

 void ROOT::Internal::RRawFileUnix::OpenImpl()

 {

+#ifdef R__SEEK64

+   fFileDes = open64(GetLocation(fUrl).c_str(), O_RDONLY);

+#else

    fFileDes = open(GetLocation(fUrl).c_str(), O_RDONLY);

+#endif

    if (fFileDes < 0) {

       throw std::runtime_error("Cannot open '" + fUrl + "', error: " + std::string(strerror(errno)));

    }

@@ -76,8 +87,13 @@

    if (fOptions.fBlockSize >= 0)

       return;

+#ifdef R__SEEK64

+   struct stat64 info;

+   int res = fstat64(fFileDes, &info;;

+#else

    struct stat info;

    int res = fstat(fFileDes, &info;;

+#endif

    if (res != 0) {

       throw std::runtime_error("Cannot call fstat on '" + fUrl + "', error: " + std::string(strerror(errno)));

    }

@@ -92,7 +108,11 @@

 {

    size_t total_bytes = 0;

    while (nbytes) {

+#ifdef R__SEEK64

+      ssize_t res = pread64(fFileDes, buffer, nbytes, offset);

+#else

       ssize_t res = pread(fFileDes, buffer, nbytes, offset);

+#endif

       if (res < 0) {

          if (errno == EINTR)

             continue;

diff -ur root-6.22.00.orig/tree/ntuple/v7/src/RMiniFile.cxx root-6.22.00/tree/ntuple/v7/src/RMiniFile.cxx

--- root-6.22.00.orig/tree/ntuple/v7/src/RMiniFile.cxx	2020-06-14 17:51:48.000000000 +0200

+++ root-6.22.00/tree/ntuple/v7/src/RMiniFile.cxx	2020-07-02 10:06:55.066204147 +0200

@@ -13,6 +13,8 @@

  * For the list of contributors see $ROOTSYS/README/CREDITS.             *

  *************************************************************************/

+#include <ROOT/RConfig.hxx>

+

 #include "ROOT/RMiniFile.hxx"

 #include <ROOT/RRawFile.hxx>

@@ -999,7 +1001,11 @@

    R__ASSERT(fFile);

    size_t retval;

    if ((offset >= 0) && (static_cast<std::uint64_t>(offset) != fFilePos)) {

+#ifdef R__SEEK64

+      retval = fseeko64(fFile, offset, SEEK_SET);

+#else

       retval = fseek(fFile, offset, SEEK_SET);

+#endif

       R__ASSERT(retval == 0);

       fFilePos = offset;

    }

@@ -1099,7 +1105,11 @@

    if (idxDirSep != std::string::npos) {

       fileName.erase(0, idxDirSep + 1);

    }

+#ifdef R__SEEK64

+   FILE *fileStream = fopen64(std::string(path.data(), path.size()).c_str(), "wb");

+#else

    FILE *fileStream = fopen(std::string(path.data(), path.size()).c_str(), "wb");

+#endif

    R__ASSERT(fileStream);

    auto writer = new RNTupleFileWriter(ntupleName);

@@ -1319,7 +1329,11 @@

    fFileSimple.Write(&strEmpty, strEmpty.GetSize());

    fFileSimple.Write(&fileRoot, fileRoot.GetSize());

    fFileSimple.fFilePos = tail;

+#ifdef R__SEEK64

+   auto retval = fseeko64(fFileSimple.fFile, tail, SEEK_SET);

+#else

    auto retval = fseek(fFileSimple.fFile, tail, SEEK_SET);

+#endif

    R__ASSERT(retval == 0);

    fFileSimple.fFilePos = tail;

 }

diff -ur root-6.22.00.orig/tree/ntuple/v7/test/ntuple.cxx root-6.22.00/tree/ntuple/v7/test/ntuple.cxx

--- root-6.22.00.orig/tree/ntuple/v7/test/ntuple.cxx	2020-06-14 17:51:48.000000000 +0200

+++ root-6.22.00/tree/ntuple/v7/test/ntuple.cxx	2020-07-02 10:10:54.409737807 +0200

@@ -1,3 +1,5 @@

+#include <ROOT/RConfig.hxx>

+

 #include <ROOT/RColumnModel.hxx>

 #include <ROOT/RDataFrame.hxx>

 #include <ROOT/RNTuple.hxx>

@@ -891,10 +893,17 @@

          ntuple->Fill();

       }

    }

+#ifdef R__SEEK64

+   FILE *file = fopen64(fileGuard.GetPath().c_str(), "rb");

+   ASSERT_TRUE(file != nullptr);

+   EXPECT_EQ(0, fseeko64(file, 0, SEEK_END));

+   EXPECT_GT(ftello64(file), 2048LL * 1024LL * 1024LL);

+#else

    FILE *file = fopen(fileGuard.GetPath().c_str(), "rb");

    ASSERT_TRUE(file != nullptr);

    EXPECT_EQ(0, fseek(file, 0, SEEK_END));

    EXPECT_GT(ftell(file), 2048LL * 1024LL * 1024LL);

+#endif

    fclose(file);

    auto ntuple = RNTupleReader::Open("myNTuple", fileGuard.GetPath());