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OSX 10.14 Mojave - man page for check_int32_div (mojave section 3)

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

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
#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);
The check_<type>_<operation>(x, y, err) family of functions perform the specified arithmetic operation (addition, subtraction, multiplica- tion, 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 persists in the err argu- ment until err is reset to CHECKINT_NO_ERROR.
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.
/* 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;
The check_<type>_<operation>() functions may fail if: [CHECKINT_TYPE_ERROR] operand is of an incompatible type
The checkint() API was introduced in Mac OS X 10.5.
April 20, 2007 BSD