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CHECK_INT32_ADD(3)       BSD Library Functions Manual       CHECK_INT32_ADD(3)

NAME
     check_int32_add, check_uint32_add, check_int64_add, check_uint64_add, check_int32_sub,
     check_uint32_sub, check_int64_sub, check_uint64_sub, check_int32_mul, check_uint32_mul,
     check_int64_mul, check_uint64_mul, check_int32_div, check_uint32_div, check_int64_div,
     check_uint64_div, -- detect overflow in arithmetic

SYNOPSIS
     #include <checkint.h>

     int32_t
     check_int32_add(int x, int y, int *err);

     uint32_t
     check_uint32_add(int x, int y, int *err);

     int64_t
     check_int64_add(int x, int y, int *err);

     uint64_t
     check_uint64_add(int x, int y, int *err);

     int32_t
     check_int32_sub(int x, int y, int *err);

     uint32_t
     check_uint32_sub(int x, int y, int *err);

     int64_t
     check_int64_sub(int x, int y, int *err);

     uint64_t
     check_uint64_sub(int x, int y, int *err);

     int32_t
     check_int32_mul(int x, int y, int *err);

     uint32_t
     check_uint32_mul(int x, int y, int *err);

     int64_t
     check_int64_mul(int x, int y, int *err);

     uint64_t
     check_uint64_mul(int x, int y, int *err);

     int32_t
     check_int32_div(int x, int y, int *err);

     uint32_t
     check_uint32_div(int x, int y, int *err);

     int64_t
     check_int64_div(int x, int y, int *err);

     uint64_t
     check_uint64_div(int x, int y, int *err);

DESCRIPTION
     The check_<type>_<operation>(x, y, err) family of functions perform the specified arithmetic operation
     (addition, subtraction, multiplication, or division) with the left operand of x and right operand of y
     and return the arithmetic result with the specified type.

     Either operand x or y (or both) can be of any type that is compatible to signed or unsigned 8-bit,
     16-bit, 32-bit, or 64-bit integers.

     The err argument is or'ed by flags in the function to indicate if an overflow has occurred.  The possi-ble possible
     ble flag values are:

           CHECKINT_NO_ERROR               no overflow has occurred
           CHECKINT_OVERFLOW_ERROR         overflow has occurred
           CHECKINT_TYPE_ERROR             operand is of an incompatible type

     The err argument is not cleared in calls to the check_<type>_<operation>(x, y, err) functions.
     Detected overflow persists in the err argument until err is reset to CHECKINT_NO_ERROR.

RETURN VALUES
     If successful, the check_<type>_<operation>() functions will return the arithmetic result of performing
     the operation with left operand x and right operand y (even when overflow error occurs).

     If any other error occurs, the return value is -1 and the argument err will be set to indicate the
     error.

EXAMPLES
           /* Create a variable to store overflow flag */
           int32_t err = CHECKINT_NO_ERROR;
           /* Use checkint API to perform an arithmetic operation and
            * store result in variable. */
           int32_t arithmetic_result = check_int32_add(UINT_MAX, 1, &err);
           /* Check status of overflow flag */
           if (err & CHECKINT_OVERFLOW_ERROR) {
               /* Perform overflow resolution code */
               fprintf(stderr, "Overflow detected!\n");
           }
           /* Check for type error */
           else if (err & CHECKINT_TYPE_ERROR) {
               /* Deal with incompatible types error */
               fprintf(stderr, "Incompatible types!\n");
           }
           /* Reset overflow flag for next operation */
           err = CHECKINT_NO_ERROR;


ERRORS
     The check_<type>_<operation>() functions may fail if:

           [CHECKINT_TYPE_ERROR]           operand is of an incompatible type

HISTORY
     The checkint() API was introduced in Mac OS X 10.5.

BSD                             April 20, 2007                             BSD