Index: flang/runtime/unit.cpp =================================================================== --- flang/runtime/unit.cpp +++ flang/runtime/unit.cpp @@ -279,16 +279,23 @@ positionInRecord + static_cast(bytes))}; if (openRecl) { // Check for fixed-length record overrun, but allow for - // the unformatted sequential record header & footer, if any. - int extra{access == Access::Sequential && isUnformatted && *isUnformatted - ? static_cast(sizeof(std::uint32_t)) - : 0}; - if (furthestAfter > 2 * extra + *openRecl) { + // sequential record termination. + int extra{0}; + int header{0}; + if (access == Access::Sequential) { + if (isUnformatted.value_or(false)) { + // record header + footer + header = static_cast(sizeof(std::uint32_t)); + extra = 2 * header; + } else { + extra = 1; // newline + } + } + if (furthestAfter > extra + *openRecl) { handler.SignalError(IostatRecordWriteOverrun, "Attempt to write %zd bytes to position %jd in a fixed-size record " "of %jd bytes", - bytes, - static_cast(positionInRecord - extra /*header*/), + bytes, static_cast(positionInRecord - header), static_cast(*openRecl)); return false; } @@ -487,15 +494,17 @@ } else { // Direction::Output bool ok{true}; RUNTIME_CHECK(handler, isUnformatted.has_value()); - if (openRecl && furthestPositionInRecord < *openRecl) { - // Pad remainder of fixed length record - WriteFrame(frameOffsetInFile_, recordOffsetInFrame_ + *openRecl, handler); - std::memset(Frame() + recordOffsetInFrame_ + furthestPositionInRecord, - isUnformatted.value_or(false) ? 0 : ' ', - *openRecl - furthestPositionInRecord); - furthestPositionInRecord = *openRecl; - } - if (!(openRecl && access == Access::Direct)) { + if (openRecl && access == Access::Direct) { + if (furthestPositionInRecord < *openRecl) { + // Pad remainder of fixed length record + WriteFrame( + frameOffsetInFile_, recordOffsetInFrame_ + *openRecl, handler); + std::memset(Frame() + recordOffsetInFrame_ + furthestPositionInRecord, + isUnformatted.value_or(false) ? 0 : ' ', + *openRecl - furthestPositionInRecord); + furthestPositionInRecord = *openRecl; + } + } else { positionInRecord = furthestPositionInRecord; if (isUnformatted.value_or(false)) { // Append the length of a sequential unformatted variable-length record