上有问题
valgrind——tool=memcheck——leak-check=yes ./9算法(这是我从valgrind得到的错误信息)
==3110== Invalid write of size 1
==3110== at 0x400FD8: main (9algorithm.c:223)
==3110== Address 0x51fc372 is 0 bytes after a block of size 2 alloc'd
==3110== at 0x4C2C6AE: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400FF5: main (9algorithm.c:226)
==3110==
==3110== Invalid write of size 1
==3110== at 0x40102F: main (9algorithm.c:233)
==3110== Address 0x52ff657 is 1 bytes after a block of size 1,990 alloc'd
==3110== at 0x4C2C6AE: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400FF5: main (9algorithm.c:226)
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C3052E: strstr (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400B20: mag_parse (9algorithm.c:63)
==3110== by 0x40105B: main (9algorithm.c:235)
==3110==
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C3052E: strstr (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400C56: place_parse (9algorithm.c:103)
==3110== by 0x401088: main (9algorithm.c:236)
==3110==
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C3052E: strstr (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400DB2: time_parse (9algorithm.c:145)
==3110== by 0x4010B6: main (9algorithm.c:237)
==3110==
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4E80D0F: vfprintf (vfprintf.c:1655)
==3110== by 0x4E87FF8: printf (printf.c:34)
==3110== by 0x401131: main (9algorithm.c:239)
==3110==
(null), Magnitude : (null), (null)
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C2B5C2: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x4011DF: main (9algorithm.c:326)
==3110==
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C2B5C2: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x4011EF: main (9algorithm.c:327)
==3110==
==3110== Conditional jump or move depends on uninitialised value(s)
==3110== at 0x4C2B5C2: free (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x4011FF: main (9algorithm.c:328)
==3110==
==3110==
==3110== HEAP SUMMARY:
==3110== in use at exit: 3,579 bytes in 2 blocks
==3110== total heap usage: 1,794 allocs, 1,792 frees, 1,623,686 bytes allocated
==3110==
==3110== 3,579 bytes in 2 blocks are definitely lost in loss record 1 of 1
==3110== at 0x4C2C6AE: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==3110== by 0x400FF5: main (9algorithm.c:226)
==3110==
==3110== LEAK SUMMARY:
==3110== definitely lost: 3,579 bytes in 2 blocks
==3110== indirectly lost: 0 bytes in 0 blocks
==3110== possibly lost: 0 bytes in 0 blocks
==3110== still reachable: 0 bytes in 0 blocks
==3110== suppressed: 0 bytes in 0 blocks
==3110==
==3110== For counts of detected and suppressed errors, rerun with: -v
==3110== Use --track-origins=yes to see where uninitialised values come from
==3110== ERROR SUMMARY: 1799 errors from 10 contexts (suppressed: 2 from 2)
当我运行。/9算法时，它给我这个错误:
, Magnitude : , (null)
*** Error in `./9algorithm': free(): invalid pointer: 0x00007fff8a4d7a10 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x80996)[0x7f48a7eb3996]
./9algorithm[0x4011e0]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7f48a7e54de5]
./9algorithm[0x400839]
======= Memory map: ========
00400000-00402000 r-xp 00000000 08:07 1965405 /home/Desktop/9algorithm
00601000-00602000 r--p 00001000 08:07 1965405 /home/Desktop/9algorithm
00602000-00603000 rw-p 00002000 08:07 1965405 /home/Desktop/9algorithm
01377000-01398000 rw-p 00000000 00:00 0 [heap]
7f48a7c1d000-7f48a7c32000 r-xp 00000000 08:07 654085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f48a7c32000-7f48a7e31000 ---p 00015000 08:07 654085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f48a7e31000-7f48a7e32000 r--p 00014000 08:07 654085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f48a7e32000-7f48a7e33000 rw-p 00015000 08:07 654085 /lib/x86_64-linux-gnu/libgcc_s.so.1
7f48a7e33000-7f48a7ff0000 r-xp 00000000 08:07 658204 /lib/x86_64-linux-gnu/libc-2.17.so
7f48a7ff0000-7f48a81f0000 ---p 001bd000 08:07 658204 /lib/x86_64-linux-gnu/libc-2.17.so
7f48a81f0000-7f48a81f4000 r--p 001bd000 08:07 658204 /lib/x86_64-linux-gnu/libc-2.17.so
7f48a81f4000-7f48a81f6000 rw-p 001c1000 08:07 658204 /lib/x86_64-linux-gnu/libc-2.17.so
7f48a81f6000-7f48a81fb000 rw-p 00000000 00:00 0
7f48a81fb000-7f48a821e000 r-xp 00000000 08:07 658180 /lib/x86_64-linux-gnu/ld-2.17.so
7f48a8403000-7f48a8406000 rw-p 00000000 00:00 0
7f48a8418000-7f48a841d000 rw-p 00000000 00:00 0
7f48a841d000-7f48a841e000 r--p 00022000 08:07 658180 /lib/x86_64-linux-gnu/ld-2.17.so
7f48a841e000-7f48a8420000 rw-p 00023000 08:07 658180 /lib/x86_64-linux-gnu/ld-2.17.so
7fff8a4b9000-7fff8a4da000 rw-p 00000000 00:00 0 [stack]
7fff8a5ca000-7fff8a5cc000 r-xp 00000000 00:00 0 [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]
Aborted (core dumped)
c(第223行-无效的写入大小)(第233行-无效的写入大小)(第226行——地址……块之后....)
int main()
{
FILE *fp = 0;
char *filename = "e_quake.txt";
struct information *e_quakePtr = 0;
char *line = 0;
char c = 0;
int k = 0;
int h = 0;
fp = fopen(filename,"r");
if(!fp){
printf("Unable to open file: %sn",filename);
return -1;
}
e_quakePtr = (struct information *)malloc(1 * sizeof(struct information));
if(!e_quakePtr){
printf("Error on malloc on e_quakePtr");
return 1;
}
line = (char *)malloc(1 * sizeof(char));
if(!line){
printf("Error on malloc on line");
return 1;
}
while( (c = fgetc(fp)) != EOF ){
if(c != 'n'){
line[h] = c;
h++;
line = (char *)realloc(line,(h+1) * sizeof(char));
if(!line){
printf("Error on realloc on line");
return 1;
}
}else{
h++;
line[h] = 0;
e_quakePtr[k].mag = mag_parse(line);
e_quakePtr[k].place = place_parse(line);
e_quakePtr[k].time = time_parse(line);
printf("%s, Magnitude : %s, %sn",e_quakePtr[k].place, e_quakePtr[k].mag, e_quakePtr[k].time);
k++;
e_quakePtr = (struct information *)realloc(e_quakePtr,(k+1) * sizeof(struct information));
if(!e_quakePtr){
printf("Error on realloc on e_quakePtr");
return 1;
}
h = 0;
free(line);
line = (char *)malloc(1 * sizeof(char));
if(!line){
printf("Error on malloc on line");
return 1;
}
}
free(e_quakePtr->mag);
free(e_quakePtr->place);
free(e_quakePtr->time);
free(e_quakePtr);
fclose(fp);
return 0;
}
你的逻辑在
有一个错误 h++;
line[h] = 0;
这个字符没有被分配，我想。
也:
- 铸造的回归
malloc和朋友容易隐藏微妙的漏洞，不要那样做。 -
sizeof(char)定义为1
你不应该那样做。代替
char *temp;
temp = realloc(line, (h+1) * sizeof(char));
if(!temp){
printf("Error on realloc on line");
free(line);
return 1;
}
else{line = temp;}
瓦尔特
每次写
line = (char *)malloc(1 * sizeof(char));
只为line分配一个字符。可能你指的不止一个字符，就像你使用realloc时那样。每次在循环中，只要没有遇到换行符，你也可以将它的大小设为1，这只会覆盖前一个指针，泄漏1个内存字符。<-编辑好吧，我注意到你在那之前释放了它，但分配1个字符仍然没有多大意义。你可以去掉这两行，循环中的下一个realloc会帮你解决:
free(line);
line = (char *)malloc(1 * sizeof(char));
顺便说一句，sizeof(char)在C标准中定义为1，所以
1 * sizeof(char) == 1 * 1 == 1
sizeof返回类型的"宽度是多少字符"。这就像问"char中的字符数"
如果您想确保它是类型感知的分配，常见的最佳实践是:
line = malloc(n * sizeof(*line));
这样，即使*行的类型改变了，malloc仍然是好的。
下面是一些有用的Valgrind提示-
节选自Valgrind文档