GCC10对sprintf的一个严格检查的修正方法.

测试代码:

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

int main(){
    char *buf;
    buf = (char *)malloc(1000);
    for(uint8_t i = 0;i < 10;i++){
        sprintf(buf, "%s:%d\n", buf, i);
    }
    printf("%s",buf);
}

使用严格的编译:

gcc -Wall -Werror 1.c

得到错误:

1.c: In function ‘main’:
1.c:9:9: error: passing argument 1 to restrict-qualified parameter aliases with argument 3 [-Werror=restrict]
    9 |         sprintf(buf, "%s:%d\n", buf, i);
      |         ^~~~~~~
cc1: all warnings being treated as errors

当然也有可能得到类似如下错误.

argument 3 overlaps destination object

主要是因为套娃,那么就把套娃的事情外置.

int main(){
    char *buf;
    buf = (char *)malloc(1000);
    size_t extra_len = strlen(buf);
    for(uint8_t i = 0;i < 10;i++){
       extra_len += sprintf(buf+extra_len, ":%d\n", i);
    }
    printf("%s",buf);
}

问题解决了.