复制文件，但误差双倍免费或损坏用C

Question

int main(int argc, char **argv) 
{ 
    FILE *fe, *fs; 
    unsigned char buffer[2048]; 
    int bytesreader; 

    fe = fopen(argv[1], "rb"); 

    fs = fopen(argv[2], "wb"); 


    while((bytesreader = fread(buffer, 1, 2048, fe))) 
     fwrite(buffer, 1, bytesreader, fs); 

    fclose(fe); 
    fclose(fs); 
    return 0; 
} 

而且我的错误是...

*** glibc detected *** ./doc2: double free or corruption (top): 0x096b7008 *** 

对不起，现在是正确的，但我不undertand。我的失败在哪里？

Answer 1

您需要检查的fopen（）函数的返回值0

调用FCLOSE（）0的结果您所看到的错误。

另外，检查参数的有效范围argc。

int main(int argc, char **argv) 
{ 
    FILE *fe, *fs; 
    unsigned char buffer[2048]; 
    int bytesreader; 

    if(argc != 3) { 
     fprintf(stderr, "usage: %s file1 file2\n", argv[0]); 
     exit(1); 
    } 

    fe = fopen(argv[1], "rb"); 
    if(fe == 0) { 
     fprintf(stderr, "%s: Failed to open %s for read\n", argv[0], argv[1]); 
     exit(1); 
    } 

    fs = fopen(argv[2], "wb"); 
    if(fs == 0) { 
     fprintf(stderr, "%s: Failed to open %s for write\n", argv[0], argv[2]); 
     exit(1); 
    } 


    while((bytesreader = fread(buffer, 1, 2048, fe))) 
     fwrite(buffer, 1, bytesreader, fs); 

    fclose(fe); 
    fclose(fs); 
    return 0; 
}