1 #ifndef ERROR_H

     2 #define ERROR_H

     3 

     4 /*

     5  * Error-handling functions

     6  */

     7 #include <errno.h>

     8 

     9 /*

    10  * Type used for error codes is an explicitly *unsigned* int, meaning that error codes themselves are positive.

    11  * Negative error codes also exist in some places, and they are just a negative err_t.

    12  */

    13 typedef unsigned int err_t;

    14 

    15 /*

    16  * List of defined error codes, organized mostly by function name

    17  */

    18 enum error_code {

    19     ERR_CALLOC                  = 0x000100,

    20     

    21     // network resolver errors

    22     ERR_GETADDRINFO             = 0x000200,

    23     ERR_GETADDRINFO_EMPTY       = 0x000201,     /* No valid results */

    24 

    25     // low-level network errors

    26     ERR_SOCKET                  = 0x000301,

    27     ERR_CONNECT                 = 0x000302,

    28 

    29     // low-level IO errors

    30     ERR_READ                    = 0x000401,

    31     ERR_WRITE                   = 0x000402,

    32 };

    33 

    34 /*

    35  * An error code and associated extra infos

    36  */

    37 struct error_info {

    38     /* The base error code */

    39     err_t code;

    40 

    41     /* Additional detail info, usually some third-part error code */

    42     unsigned int extra;

    43 };

    44 

    45 /** No error, evaulates as logical false */

    46 #define SUCCESS (0)

    47 

    48 /* Evaulates to error_info.code as lvalue */

    49 #define ERROR_CODE(err_info) ((err_info).code)

    50 

    51 /* Evaulates to error_info.extra as lvalue */

    52 #define ERROR_EXTRA(err_info) ((err_info).extra)

    53 

    54 /* Set error_info.code to SUCCESS, evaulates as zero */

    55 #define RESET_ERROR(err_info) ((err_info).code = SUCCESS)

    56 

    57 /* Compare error_info.code != 0 */

    58 #define IS_ERROR(err_info) (!!(err_info).code)

    59 

    60 /* Set error_info.code, but leave err_extra as-is. Evaluates to err_code */

    61 #define SET_ERROR(err_info, err_code) ((err_info).code = (err_code))

    62 

    63 /* Set error_info.code/extra. XXX: should evaluate to err_code */

    64 #define _SET_ERROR_EXTRA(err_info, err_code, err_extra) (err_info).code = (err_code); err_info.extra = (err_extra)

    65 #define SET_ERROR_EXTRA(err_info, err_code, err_extra) do { _SET_ERROR_EXTRA(err_info, err_code, err_extra); } while (0)

    66 

    67 /* Set error.info.code to err_code, and .extra to errno. XXX: should evaulate to err_code */

    68 #define _SET_ERROR_ERRNO(err_info, err_code) _SET_ERROR_EXTRA(err_info, err_code, errno);

    69 #define SET_ERROR_ERRNO(err_info, err_code) SET_ERROR_EXTRA(err_info, err_code, errno);

    70 

    71 /* Ss above, but also return err_code from func. XXX: use 'return SET_ERROR...' instead */

    72 #define RETURN_SET_ERROR(err_info, err_code) do { _SET_ERROR(err_info, err_code); return (err_code); } while (0)

    73 #define RETURN_SET_ERROR_EXTRA(err_info, err_code, err_extra) do { _SET_ERROR_EXTRA(err_info, err_code, err_extra); return (err_code); } while (0)

    74 #define RETURN_SET_ERROR_ERRNO(err_info, err_code) do { _SET_ERROR_ERRNO(err_info, err_code); return (err_code); } while (0)

    75 

    76 #endif