BrlAPI: Error handling

BrlAPI 0.8

Data Structures | Macros | Typedefs | Enumerations | Functions | Variables
Error handling

How to handle errors. More...

## Data Structures
struct | brlapi_error_t

## Macros
#define | brlapi_error (*brlapi_error_location())
#define | brlapi_errno (brlapi_error.brlerrno)
#define | brlapi_libcerrno (brlapi_error.libcerrno)
#define | brlapi_gaierrno (brlapi_error.gaierrno)
#define | brlapi_errfun (brlapi_error.errfun)

## Typedefs
typedef uint32_t | brlapi_packetType_t
typedef void(BRLAPI_STDCALL * | brlapi_exceptionHandler_t) (int error, brlapi_packetType_t type, const void *packet, size_t size)
typedef void(BRLAPI_STDCALL * | brlapi__exceptionHandler_t) (brlapi_handle_t *handle, int error, brlapi_packetType_t type, const void *packet, size_t size)

## Enumerations
enum | brlapi_error { BRLAPI_ERROR_SUCCESS = 0, BRLAPI_ERROR_SUCCESS = 0, BRLAPI_ERROR_NOMEM = 1, BRLAPI_ERROR_NOMEM = 1, BRLAPI_ERROR_TTYBUSY = 2, BRLAPI_ERROR_TTYBUSY = 2, BRLAPI_ERROR_DEVICEBUSY = 3, BRLAPI_ERROR_DEVICEBUSY = 3, BRLAPI_ERROR_UNKNOWN_INSTRUCTION = 4, BRLAPI_ERROR_UNKNOWN_INSTRUCTION = 4, BRLAPI_ERROR_ILLEGAL_INSTRUCTION = 5, BRLAPI_ERROR_ILLEGAL_INSTRUCTION = 5, BRLAPI_ERROR_INVALID_PARAMETER = 6, BRLAPI_ERROR_INVALID_PARAMETER = 6, BRLAPI_ERROR_INVALID_PACKET = 7, BRLAPI_ERROR_INVALID_PACKET = 7, BRLAPI_ERROR_CONNREFUSED = 8, BRLAPI_ERROR_CONNREFUSED = 8, BRLAPI_ERROR_OPNOTSUPP = 9, BRLAPI_ERROR_OPNOTSUPP = 9, BRLAPI_ERROR_GAIERR = 10, BRLAPI_ERROR_GAIERR = 10, BRLAPI_ERROR_LIBCERR = 11, BRLAPI_ERROR_LIBCERR = 11, BRLAPI_ERROR_UNKNOWNTTY = 12, BRLAPI_ERROR_UNKNOWNTTY = 12, BRLAPI_ERROR_PROTOCOL_VERSION = 13, BRLAPI_ERROR_PROTOCOL_VERSION = 13, BRLAPI_ERROR_EOF = 14, BRLAPI_ERROR_EOF = 14, BRLAPI_ERROR_EMPTYKEY = 15, BRLAPI_ERROR_EMPTYKEY = 15, BRLAPI_ERROR_DRIVERERROR = 16, BRLAPI_ERROR_DRIVERERROR = 16, BRLAPI_ERROR_AUTHENTICATION = 17, BRLAPI_ERROR_AUTHENTICATION = 17, BRLAPI_ERROR_READONLY_PARAMETER = 18, BRLAPI_ERROR_READONLY_PARAMETER = 18 }

## Functions
void BRLAPI_STDCALL | brlapi_perror (const char *s)
brlapi_error_t *BRLAPI_STDCALL | brlapi_error_location (void)
const char *BRLAPI_STDCALL | brlapi_strerror (const brlapi_error_t *error)
size_t BRLAPI_STDCALL | brlapi_strerror_r (const brlapi_error_t *error, char *buf, size_t buflen)
const char *BRLAPI_STDCALL | brlapi_getPacketTypeName (brlapi_packetType_t type)
int BRLAPI_STDCALL | brlapi_strexception (char *buffer, size_t bufferSize, int error, brlapi_packetType_t type, const void *packet, size_t packetSize)
int BRLAPI_STDCALL | brlapi__strexception (brlapi_handle_t *handle, char *buffer, size_t bufferSize, int error, brlapi_packetType_t type, const void *packet, size_t packetSize)
brlapi_exceptionHandler_t BRLAPI_STDCALL | brlapi_setExceptionHandler (brlapi_exceptionHandler_t handler)
brlapi__exceptionHandler_t BRLAPI_STDCALL | brlapi__setExceptionHandler (brlapi_handle_t *handle, brlapi__exceptionHandler_t handler)
void BRLAPI_STDCALL | brlapi_defaultExceptionHandler (int error, brlapi_packetType_t type, const void *packet, size_t size)
void BRLAPI_STDCALL | brlapi__defaultExceptionHandler (brlapi_handle_t *handle, int error, brlapi_packetType_t type, const void *packet, size_t size)

## Variables
const char * | brlapi_errlist []
const int | brlapi_nerr
brlapi_error_t | brlapi_error
enum brlapi_error | brlapi_errno
int | brlapi_libcerrno
int | brlapi_gaierrno
const char * | brlapi_errfun

## Detailed Description

When a function fails, brlapi_errno will hold an error code to explain why it failed. It should always be reported somehow.

Although most errors are reported that way, some (called exceptions) are reported asynchronously for efficiency reasons, because they always just report a programming error. The affected functions are: brlapi_setFocus, brlapi_write* and brlapi_sendRaw. When they happen, the next call to brlapi_something will close the connection and call the exception handler. If the exception handler returns, the brlapi_something function will return an end-of-file error.

The default exception handler (brlapi_defaultExceptionHandler()) dumps the guilty packet before abort()ing. It can be replaced by calling brlapi_setExceptionHandler(). For instance, the Java and Python bindings use this for raising a Java or Python exception that may be caught.

## Macro Definition Documentation

## ◆ brlapi_errfun

#define brlapi_errfun (brlapi_error.errfun)

Cheat about the brlapi_errfun C token

## ◆ brlapi_errno

#define brlapi_errno (brlapi_error.brlerrno)

Cheat about the brlapi_errno C token

## ◆ brlapi_error

#define brlapi_error (*brlapi_error_location())

Cheat about the brlapi_error C token

## ◆ brlapi_gaierrno

#define brlapi_gaierrno (brlapi_error.gaierrno)

Cheat about the brlapi_gaierrno C token

## ◆ brlapi_libcerrno

#define brlapi_libcerrno (brlapi_error.libcerrno)

Cheat about the brlapi_libcerrno C token

## Typedef Documentation

## ◆ brlapi__exceptionHandler_t

typedef void(BRLAPI_STDCALL * brlapi__exceptionHandler_t) (brlapi_handle_t *handle, int error, brlapi_packetType_t type, const void *packet, size_t size)

## ◆ brlapi_exceptionHandler_t

typedef void(BRLAPI_STDCALL * brlapi_exceptionHandler_t) (int error, brlapi_packetType_t type, const void *packet, size_t size)

Types for exception handlers

Types of exception handlers which are to be given to brlapi_setExceptionHandler() and brlapi__setExceptionHandler().

Parameters

  handle | is the handle corresponding to the guilty connection;
  error | is a BRLAPI_ERROR_ error code;
  type | is the type of the guilty packet;
  packet | points to the content of the guilty packet (might be a little bit truncated);
  size | gives the guilty packet's size.

## ◆ brlapi_packetType_t

typedef uint32_t brlapi_packetType_t

Type for packet type. Only unsigned can cross networks, 32bits

## Enumeration Type Documentation

## ◆ brlapi_error

enum brlapi_error

BrlAPI Error codes

Enumerator
BRLAPI_ERROR_SUCCESS | Success
BRLAPI_ERROR_SUCCESS | Success
BRLAPI_ERROR_NOMEM | Not enough memory
BRLAPI_ERROR_NOMEM | Not enough memory
BRLAPI_ERROR_TTYBUSY | A connection is already running in this tty
BRLAPI_ERROR_TTYBUSY | A connection is already running in this tty
BRLAPI_ERROR_DEVICEBUSY | A connection is already using RAW or suspend mode
BRLAPI_ERROR_DEVICEBUSY | A connection is already using RAW or suspend mode
BRLAPI_ERROR_UNKNOWN_INSTRUCTION | Not implemented in protocol
BRLAPI_ERROR_UNKNOWN_INSTRUCTION | Not implemented in protocol
BRLAPI_ERROR_ILLEGAL_INSTRUCTION | Forbiden in current mode
BRLAPI_ERROR_ILLEGAL_INSTRUCTION | Forbiden in current mode
BRLAPI_ERROR_INVALID_PARAMETER | Out of range or have no sense
BRLAPI_ERROR_INVALID_PARAMETER | Out of range or have no sense
BRLAPI_ERROR_INVALID_PACKET | Invalid size
BRLAPI_ERROR_INVALID_PACKET | Invalid size
BRLAPI_ERROR_CONNREFUSED | Connection refused
BRLAPI_ERROR_CONNREFUSED | Connection refused
BRLAPI_ERROR_OPNOTSUPP | Operation not supported
BRLAPI_ERROR_OPNOTSUPP | Operation not supported
BRLAPI_ERROR_GAIERR | Getaddrinfo error
BRLAPI_ERROR_GAIERR | Getaddrinfo error
BRLAPI_ERROR_LIBCERR | Libc error
BRLAPI_ERROR_LIBCERR | Libc error
BRLAPI_ERROR_UNKNOWNTTY | Couldn't find out the tty number
BRLAPI_ERROR_UNKNOWNTTY | Couldn't find out the tty number
BRLAPI_ERROR_PROTOCOL_VERSION | Bad protocol version
BRLAPI_ERROR_PROTOCOL_VERSION | Bad protocol version
BRLAPI_ERROR_EOF | Unexpected end of file
BRLAPI_ERROR_EOF | Unexpected end of file
BRLAPI_ERROR_EMPTYKEY | Key file empty
BRLAPI_ERROR_EMPTYKEY | Key file empty
BRLAPI_ERROR_DRIVERERROR | Packet returned by driver too large
BRLAPI_ERROR_DRIVERERROR | Packet returned by driver too large
BRLAPI_ERROR_AUTHENTICATION | Authentication failed
BRLAPI_ERROR_AUTHENTICATION | Authentication failed
BRLAPI_ERROR_READONLY_PARAMETER | Parameter can not be changed
BRLAPI_ERROR_READONLY_PARAMETER | Parameter can not be changed

## Function Documentation

## ◆ brlapi__defaultExceptionHandler()

void BRLAPI_STDCALL brlapi__defaultExceptionHandler | ( | brlapi_handle_t * | handle,
|  | int | error,
|  | brlapi_packetType_t | type,
|  | const void * | packet,
|  | size_t | size
| ) |  |

## ◆ brlapi__setExceptionHandler()

brlapi__exceptionHandler_t BRLAPI_STDCALL brlapi__setExceptionHandler | ( | brlapi_handle_t * | handle,
|  | brlapi__exceptionHandler_t | handler
| ) |  |

## ◆ brlapi__strexception()

int BRLAPI_STDCALL brlapi__strexception | ( | brlapi_handle_t * | handle,
|  | char * | buffer,
|  | size_t | bufferSize,
|  | int | error,
|  | brlapi_packetType_t | type,
|  | const void * | packet,
|  | size_t | packetSize
| ) |  |

## ◆ brlapi_defaultExceptionHandler()

void BRLAPI_STDCALL brlapi_defaultExceptionHandler | ( | int | error,
|  | brlapi_packetType_t | type,
|  | const void * | packet,
|  | size_t | size
| ) |  |

## ◆ brlapi_error_location()

brlapi_error_t* BRLAPI_STDCALL brlapi_error_location | ( | void |  | ) |

Get per-thread error location

In multithreaded software, brlapi_error is thread-specific, so api.h cheats about the brlapi_error token and actually calls brlapi_error_location().

This gets the thread specific location of global variable brlapi_error

## ◆ brlapi_getPacketTypeName()

const char* BRLAPI_STDCALL brlapi_getPacketTypeName | ( | brlapi_packetType_t | type | ) |

Get plain packet type

brlapi_getPacketTypeName() returns the plain packet type name corresponding to its argument.

## ◆ brlapi_perror()

void BRLAPI_STDCALL brlapi_perror | ( | const char * | s | ) |

Print a BrlAPI error message

brlapi_perror() reads brlapi_error, and acts just like perror().

## ◆ brlapi_setExceptionHandler()

brlapi_exceptionHandler_t BRLAPI_STDCALL brlapi_setExceptionHandler | ( | brlapi_exceptionHandler_t | handler | ) |

Set a new exception handler

brlapi_setExceptionHandler() replaces the previous exception handler with the handler parameter. The previous exception handler is returned to make chaining error handlers possible.

The default handler just prints the exception and abort()s.

## ◆ brlapi_strerror()

const char* BRLAPI_STDCALL brlapi_strerror | ( | const brlapi_error_t * | error | ) |

Get plain error message

brlapi_strerror() returns the plain error message corresponding to its argument. Since the message is a constant string, the application must not free it. Also, this makes it unsafe in threaded environments, brlapi_strerror_r() should be used instead in that case.

## ◆ brlapi_strerror_r()

size_t BRLAPI_STDCALL brlapi_strerror_r | ( | const brlapi_error_t * | error,
|  | char * | buf,
|  | size_t | buflen
| ) |  |

Store plain error message

brlapi_strerror_r() stores the plain error message corresponding to its `error` argument. `buflen` has to be set to the size of `buf`, and brlapi_strerror_r() will store at most `buflen` bytes in `buf`. If `buflen` is not large enough for the whole error message, it will be truncated, but a trailing \0 character will still be set at buf[buflen-1].

Returns
  the number of characters that should have been stored in `buf` (without the trailing \0 character). A value greater or equal to `buflen` thus means that the output was truncated.

If `buflen` is set to 0, `buf` can be set to NULL, and brlapi_strerror_r will thus only return the number of characters that would have been stored (without the trailing \0 character).

## ◆ brlapi_strexception()

int BRLAPI_STDCALL brlapi_strexception | ( | char * | buffer,
|  | size_t | bufferSize,
|  | int | error,
|  | brlapi_packetType_t | type,
|  | const void * | packet,
|  | size_t | packetSize
| ) |  |

Describes an exception

brlapi_strexception() puts a text describing the given exception in buffer.

The beginning of the guilty packet is dumped as a sequence of hex bytes.

Returns
  the size of the text describing the exception, following snprintf()'s semantics.

## Variable Documentation

## ◆ brlapi_errfun

const char* brlapi_errfun
| extern

Shorthand for brlapi_error.errfun

## ◆ brlapi_errlist

const char* brlapi_errlist[]
| extern

Error message list

These are the string constants used by brlapi_perror().

## ◆ brlapi_errno

enum brlapi_error brlapi_errno
| extern

Shorthand for brlapi_error.errno

## ◆ brlapi_error

brlapi_error_t brlapi_error
| extern

Global variable brlapi_error

brlapi_error is a global left-value containing the last error information. Its errno field is not reset to BRLAPI_ERROR_SUCCESS on success.

This information may be copied in brlapi_error_t variables for later use with the brlapi_strerror function.

## ◆ brlapi_gaierrno

int brlapi_gaierrno
| extern

Shorthand for brlapi_error.gaierrno

## ◆ brlapi_libcerrno

int brlapi_libcerrno
| extern

Shorthand for brlapi_error.libcerrno

## ◆ brlapi_nerr

const int brlapi_nerr
| extern

Number of error messages