39 lines
1.1 KiB
C
39 lines
1.1 KiB
C
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#include <stdio.h>
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#include <stdint.h>
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#include <inttypes.h>
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#include <stdlib.h>
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__attribute__((ms_abi)) void *memmove(void *, const void *, size_t);
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__attribute__((ms_abi)) void *memset(void *, int, size_t);
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void output_memmove(const char *str) {
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puts(str);
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}
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int main(void) {
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char str[] = "1234567890";
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puts(str);
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memmove(str + 4, str + 3, 3); // copy from [4,5,6] to [5,6,7]
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puts(str);
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memmove(str + 3, str + 4, 3); // copy from [4,5,6] to [5,6,7]
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puts(str);
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memset(str + 3, '0' + 7, 3);
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puts(str);
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for (int i = 0; i <= 10; i++)
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printf("str[%d]=%d (%c)\n", i, str[i], str[i]);
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// setting effective type of allocated memory to be int
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int *p = malloc(3 * sizeof(int)); // allocated memory has no effective type
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int arr[3] = {1, 2, 3};
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memmove(p, arr, 3 * sizeof(int)); // allocated memory now has an effective type
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printf("%d %d %d\n", p[0], p[1], p[2]);
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// reinterpreting data
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double d = 0.1;
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// int64_t n = *(int64_t*)(&d); // strict aliasing violation
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int64_t n;
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memmove(&n, &d, sizeof d); // OK
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printf("%a is %" PRIx64 " as an int64_t\n", d, n);
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}
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