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Diffstat (limited to 'erts/doc/src/zlib.xml')
| -rw-r--r-- | erts/doc/src/zlib.xml | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/erts/doc/src/zlib.xml b/erts/doc/src/zlib.xml index e1924fffee..04fcc4285d 100644 --- a/erts/doc/src/zlib.xml +++ b/erts/doc/src/zlib.xml @@ -315,6 +315,15 @@ list_to_binary([B1,B2])</pre> <c><anno>WindowBits</anno></c> value suppresses the zlib header (and checksum) from the stream. Notice that the zlib source mentions this only as a undocumented feature.</p> + <warning> + <p>Due to a known bug in the underlying zlib library, <c>WindowBits</c> values 8 and -8 + do not work as expected. In zlib versions before 1.2.9 values + 8 and -8 are automatically changed to 9 and -9. <em>From zlib version 1.2.9 + value -8 is rejected</em> causing <c>zlib:deflateInit/6</c> to fail + (8 is still changed to 9). It also seem possible that future versions + of zlib may fix this bug and start accepting 8 and -8 as is.</p> + <p>Conclusion: Avoid values 8 and -8 unless you know your zlib version supports them.</p> + </warning> </item> <tag><c><anno>MemLevel</anno></c></tag> <item> |