想试验下strcpy_s

网上搜索说要这么写

#define __STDC_WANT_LIB_EXT1__ 1

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    char *src = "Take the test.";//  src[0] = 'M' ; // this would be undefined behavior
    char dst[strlen(src) + 1]; // +1 to accomodate for the null terminator    strcpy(dst, src);
    dst[0] = 'M'; // OK    printf("src = %s\ndst = %s\n", src, dst);

#ifdef __STDC_LIB_EXT1__    
        set_constraint_handler_s(ignore_handler_s);
    int r = strcpy_s(dst, sizeof dst, src);    
        printf("dst = \"%s\", r = %d\n", dst, r);
    r = strcpy_s(dst, sizeof dst, "Take even more tests.");    
        printf("dst = \"%s\", r = %d\n", dst, r);
#endif

}

编译的时候也添加了 -std=c11

gcc版本是gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04.2)  应该也支持c11

但是编译完执行，什么都没有打印出来
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