-1
私は、コードのこの作品があります。私が何をしようとしています何ボイドポインタ、メモリの割り当てとvalgrindの
void *data = calloc(1, sizeof(char)+sizeof(float)+sizeof(char)); // line 56
*((char *) data) = 'a'; // line 58
*((float *) data + sizeof(char)) = 0.2f; // line 59
*((char *) data + sizeof(float) + sizeof(char)) = 'a'; // line 60
printf("%c ", *((char *) data)); // line 62
printf("%f ", *((float *) data + sizeof(char))); // line 63
printf("%c ", *((char *) data + sizeof(float) + sizeof(char))); // line 64
printf("\n");
そしてbasiclyを同じメモリ領域に変数とその値の様々なタイプを保存しています。これを行うには、voidポインターと変数のオフセットを使用していますが、すべて正常に動作しますが、valgrindは無効な読み書きをしていることを続けています。私の意見ではすべてが理にかなっていますが、バンググラインドは意見が異なります。 valgrindのように怒っている理由を誰かが私には理解を助けることができれば
==5829== Memcheck, a memory error detector
==5829== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==5829== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==5829== Command: ./a.out
==5829==
==5829== Invalid write of size 4
==5829== at 0x400909: main (Main.c:59)
==5829== Address 0x51f6044 is 4 bytes inside a block of size 6 alloc'd
==5829== at 0x4C2AA98: calloc (vg_replace_malloc.c:711)
==5829== by 0x4008ED: main (Main.c:56)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E83CEE: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E83ED6: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E7D9C0: __mpn_extract_double (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E843C9: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E83FFA: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E845E2: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E85504: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C2E8: __mpn_lshift (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85508: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C2EB: __mpn_lshift (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85508: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E85546: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85568: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E856CC: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85A54: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C904: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85A6F: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C98F: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85A6F: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7CA02: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85A6F: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E85A83: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85A92: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C3F8: __mpn_rshift (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85DF1: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C41D: __mpn_rshift (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85DF1: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E849F1: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C904: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E849F8: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C928: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E849F8: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84A40: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E836D9: hack_digit (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E84A58: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C904: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E836E0: hack_digit (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E84A58: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Use of uninitialised value of size 8
==5829== at 0x4E7C928: __mpn_mul_1 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E836E0: hack_digit (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E84A58: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84A63: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84A71: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85093: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85099: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E853BD: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E853E2: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E8541D: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84BDF: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84E36: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84FF9: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E84FDB: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4EAFC4D: [email protected]@GLIBC_2.2.5 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85C90: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4EAFC7A: [email protected]@GLIBC_2.2.5 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E85C90: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Conditional jump or move depends on uninitialised value(s)
==5829== at 0x4E85C94: __printf_fp (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E82D9D: vfprintf (in /usr/lib64/libc-2.22.so)
==5829== by 0x4E88D28: printf (in /usr/lib64/libc-2.22.so)
==5829== by 0x400951: main (Main.c:63)
==5829==
==5829== Syscall param write(buf) points to uninitialised byte(s)
==5829== at 0x4F27C10: __write_nocancel (in /usr/lib64/libc-2.22.so)
==5829== by 0x4EAE14E: [email protected]@GLIBC_2.2.5 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4EAF8F8: [email protected]@GLIBC_2.2.5 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4EAFD0A: [email protected]@GLIBC_2.2.5 (in /usr/lib64/libc-2.22.so)
==5829== by 0x4EA6A47: putchar (in /usr/lib64/libc-2.22.so)
==5829== by 0x40097A: main (Main.c:65)
==5829== Address 0x4022004 is in a rw- anonymous segment
==5829==
a 0.199592 a
==5829==
==5829== HEAP SUMMARY:
==5829== in use at exit: 6 bytes in 1 blocks
==5829== total heap usage: 1 allocs, 0 frees, 6 bytes allocated
==5829==
==5829== LEAK SUMMARY:
==5829== definitely lost: 6 bytes in 1 blocks
==5829== indirectly lost: 0 bytes in 0 blocks
==5829== possibly lost: 0 bytes in 0 blocks
==5829== still reachable: 0 bytes in 0 blocks
==5829== suppressed: 0 bytes in 0 blocks
==5829== Rerun with --leak-check=full to see details of leaked memory
==5829==
==5829== For counts of detected and suppressed errors, rerun with: -v
==5829== Use --track-origins=yes to see where uninitialised values come from
==5829== ERROR SUMMARY: 103 errors from 42 contexts (suppressed: 0 from 0)
、それは素晴らしいことだ：
はここでvalgrindのの出力です。
ありがとうございました！
データのローカリティを達成しようとしている場合は、単純に構造体を作成できます。複数の型に対して変数を使用しようとしている場合は、おそらく共用体を使用するべきです。あなたが実験しているだけなら、クールですが、これは生産コードにとって恐ろしい考えです。 – bodangly
CPUの種類によってはアラインメントに問題があります。したがって、次の文字ポイントのアドレスからcharより大きいデータを直接参照解除するだけでは使用できません。 – BLUEPIXY