# 7.3.6. Return code

## 7.3.6.1. Summary

Return code is used to show whether a processing is succeeded or not. If the processing is not succeeded, return code shows error type.

Return code is used in C API and query API. You can check return code via `grn_ctx_t::rc` in C API. You can check return code by looking the header element in query API. See Output format about the header element in query API.

## 7.3.6.2. List

Here is a list of return codes. `GRN_SUCCESS` (= 0) means that the processing is succeeded. Return codes that have negative value show error type. `GRN_END_OF_DATA` is a special return code. It is used only C API. It is not showen in query API.

- 0: `GRN_SUCCESS`

- 1: `GRN_END_OF_DATA`

- -1: `GRN_UNKNOWN_ERROR`

- -2: `GRN_OPERATION_NOT_PERMITTED`

- -3: `GRN_NO_SUCH_FILE_OR_DIRECTORY`

- -4: `GRN_NO_SUCH_PROCESS`

- -5: `GRN_INTERRUPTED_FUNCTION_CALL`

- -6: `GRN_INPUT_OUTPUT_ERROR`

- -7: `GRN_NO_SUCH_DEVICE_OR_ADDRESS`

- -8: `GRN_ARG_LIST_TOO_LONG`

- -9: `GRN_EXEC_FORMAT_ERROR`

- -10: `GRN_BAD_FILE_DESCRIPTOR`

- -11: `GRN_NO_CHILD_PROCESSES`

- -12: `GRN_RESOURCE_TEMPORARILY_UNAVAILABLE`

- -13: `GRN_NOT_ENOUGH_SPACE`

- -14: `GRN_PERMISSION_DENIED`

- -15: `GRN_BAD_ADDRESS`

- -16: `GRN_RESOURCE_BUSY`

- -17: `GRN_FILE_EXISTS`

- -18: `GRN_IMPROPER_LINK`

- -19: `GRN_NO_SUCH_DEVICE`

- -20: `GRN_NOT_A_DIRECTORY`

- -21: `GRN_IS_A_DIRECTORY`

- -22: `GRN_INVALID_ARGUMENT`

- -23: `GRN_TOO_MANY_OPEN_FILES_IN_SYSTEM`

- -24: `GRN_TOO_MANY_OPEN_FILES`

- -25: `GRN_INAPPROPRIATE_I_O_CONTROL_OPERATION`

- -26: `GRN_FILE_TOO_LARGE`

- -27: `GRN_NO_SPACE_LEFT_ON_DEVICE`

- -28: `GRN_INVALID_SEEK`

- -29: `GRN_READ_ONLY_FILE_SYSTEM`

- -30: `GRN_TOO_MANY_LINKS`

- -31: `GRN_BROKEN_PIPE`

- -32: `GRN_DOMAIN_ERROR`

- -33: `GRN_RESULT_TOO_LARGE`

- -34: `GRN_RESOURCE_DEADLOCK_AVOIDED`

- -35: `GRN_NO_MEMORY_AVAILABLE`

- -36: `GRN_FILENAME_TOO_LONG`

- -37: `GRN_NO_LOCKS_AVAILABLE`

- -38: `GRN_FUNCTION_NOT_IMPLEMENTED`

- -39: `GRN_DIRECTORY_NOT_EMPTY`

- -40: `GRN_ILLEGAL_BYTE_SEQUENCE`

- -41: `GRN_SOCKET_NOT_INITIALIZED`

- -42: `GRN_OPERATION_WOULD_BLOCK`

- -43: `GRN_ADDRESS_IS_NOT_AVAILABLE`

- -44: `GRN_NETWORK_IS_DOWN`

- -45: `GRN_NO_BUFFER`

- -46: `GRN_SOCKET_IS_ALREADY_CONNECTED`

- -47: `GRN_SOCKET_IS_NOT_CONNECTED`

- -48: `GRN_SOCKET_IS_ALREADY_SHUTDOWNED`

- -49: `GRN_OPERATION_TIMEOUT`

- -50: `GRN_CONNECTION_REFUSED`

- -51: `GRN_RANGE_ERROR`

- -52: `GRN_TOKENIZER_ERROR`

- -53: `GRN_FILE_CORRUPT`

- -54: `GRN_INVALID_FORMAT`

- -55: `GRN_OBJECT_CORRUPT`

- -56: `GRN_TOO_MANY_SYMBOLIC_LINKS`

- -57: `GRN_NOT_SOCKET`

- -58: `GRN_OPERATION_NOT_SUPPORTED`

- -59: `GRN_ADDRESS_IS_IN_USE`

- -60: `GRN_ZLIB_ERROR`

- -61: `GRN_LZO_ERROR`

- -62: `GRN_STACK_OVER_FLOW`

- -63: `GRN_SYNTAX_ERROR`

- -64: `GRN_RETRY_MAX`

- -65: `GRN_INCOMPATIBLE_FILE_FORMAT`

- -66: `GRN_UPDATE_NOT_ALLOWED`

- -67: `GRN_TOO_SMALL_OFFSET`

- -68: `GRN_TOO_LARGE_OFFSET`

- -69: `GRN_TOO_SMALL_LIMIT`

- -70: `GRN_CAS_ERROR`

- -71: `GRN_UNSUPPORTED_COMMAND_VERSION`

- -72: `GRN_NORMALIZER_ERROR`

- -73: `GRN_TOKEN_FILTER_ERROR`

- -74: `GRN_COMMAND_ERROR`

- -75: `GRN_PLUGIN_ERROR`

- -76: `GRN_SCORER_ERROR`

- -77: `GRN_CANCEL`

- -78: `GRN_WINDOW_FUNCTION_ERROR`

- -79: `GRN_ZSTD_ERROR`

- -80: `GRN_CONNECTION_RESET`

## 7.3.6.3. See also

- Output format shows where return code is appeared in query API response.

- GQTP: GQTP protocol also uses return code as status but it uses 2byte unsigned integer. So return codes that have negative value are statuses that have positive value in GQTP protocol. You can convert status value in GQTP protocol to return code by handling it as 2byte signed integer.

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