48 lines
986 B
C
48 lines
986 B
C
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <string.h>
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#include <stddef.h>
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typedef struct {
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uint8_t id;
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char a[16];
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uint8_t length;
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} t_testObj;
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t_testObj testObj = { .id = 0, .a = "test123", .length = 25 };
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void printTestObj(t_testObj *testObj) {
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printf("testObj: id=%d, a=%s, length=%d\n", testObj->id, testObj->a, testObj->length);
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}
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int main() {
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printf("id: %ld\n", offsetof(t_testObj, id));
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printf("a: %ld\n", offsetof(t_testObj, a));
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printf("length: %ld\n", offsetof(t_testObj, length));
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printTestObj(&testObj);
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strcpy(testObj.a, "demo234");
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printTestObj(&testObj);
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uint8_t *a1 = (uint8_t*)&testObj;
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printf("a1: %p\n", a1);
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uint8_t *a2 = ((uint8_t*)&testObj) + offsetof(t_testObj, length);
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printf("a2: %p\n", a2);
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*a2 = 35;
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printTestObj(&testObj);
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uint8_t *a3 = ((uint8_t*)&testObj) + offsetof(t_testObj, a);
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printf("a3: %p\n", a3);
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strcpy((char*)a3, "Wolfgang");
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printTestObj(&testObj);
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}
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