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 possible 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 per-
sists 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
Mac OS X 10.8 - Generated Sun Aug 26 15:57:13 CDT 2012