As documented in `zstd.h`, ZSTD_decompressBound returns `ZSTD_CONTENTSIZE_ERROR` if an error occurs (not `ZSTD_CONTENTSIZE_UNKNOWN`). This is consistent with the error checking made in ZSTD_decompressBound, particularly line 545.
As documented in `zstd.h`, ZSTD_decompressBound returns `ZSTD_CONTENTSIZE_ERROR` if an error occurs (not `ZSTD_CONTENTSIZE_UNKNOWN`). This is consistent with the error checking made in ZSTD_decompressBound, particularly line 545.