努力工作虽然努力学习c ..有这段代码：
#include <stdio.h>
/* Warning: This program is wrong on purpose. */
int main()
{
int age = 10;
int height;
printf("I am %d years old.\n");
printf("I am %d inches tall.\n", height);
return 0;
}
现在当我去运行valgrind时，我会做
valgrind --track-origins=yes ./ex4
我会得到这个：
collin@ubuntu:~/learning$ valgrind --track-origins=yes ./ex4
==14332== Memcheck, a memory error detector
==14332== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
==14332== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==14332== Command: ./ex4
==14332==
==14332== Use of uninitialised value of size 4
==14332== at 0x408C2AB: _itoa_word (_itoa.c:179)
==14332== by 0x408FB21: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x408C2B3: _itoa_word (_itoa.c:179)
==14332== by 0x408FB21: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x408CFE5: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x408D061: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x4091328: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x408D0B8: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
==14332== Conditional jump or move depends on uninitialised value(s)
==14332== at 0x408D0F1: vfprintf (vfprintf.c:1654)
==14332== by 0x409681E: printf (printf.c:34)
==14332== by 0x4061934: (below main) (libc-start.c:260)
==14332== Uninitialised value was created by a stack allocation
==14332== at 0x8048422: main (ex4.c:6)
==14332==
I am -1097264588 years old.
I am 69169152 inches tall.
==14332==
==14332== HEAP SUMMARY:
==14332== in use at exit: 0 bytes in 0 blocks
==14332== total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==14332==
==14332== All heap blocks were freed -- no leaks are possible
==14332==
==14332== For counts of detected and suppressed errors, rerun with: -v
==14332== ERROR SUMMARY: 46 errors from 7 contexts (suppressed: 0 from 0)
为什么我得到这个'低于主要'的东西而不是valgrinding告诉我问题的位置？我以为做--track-originins = yes应该解决这个问题。
感谢帮助。
这是我使用的Makefile
CFLAGS=-Wall -g
clean:
rm -f ex4
答案 0 :(得分：2)
这是因为您没有使用调试标志（-g）
编译您的程序我尝试使用-g选项编写代码并显示行号
bash-3.2$ cat test.c
#include <stdio.h>
/* Warning: This program is wrong on purpose. */
int main()
{
int age = 10;
int height;
printf("I am %d years old.\n");
printf("I am %d inches tall.\n", height);
return 0;
}
bash-3.2$ gcc -g test.c
bash-3.2$
bash-3.2$ valgrind --track-origins=yes ./a.out
==18523== Memcheck, a memory error detector
==18523== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
==18523== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==18523== Command: ./a.out
==18523==
I am -16775864 years old.
==18523== Use of uninitialised value of size 8
==18523== at 0x3FF8441E2D: _itoa_word (in /lib64/libc-2.5.so)
==18523== by 0x3FF8445212: vfprintf (in /lib64/libc-2.5.so)
==18523== by 0x3FF844D009: printf (in /lib64/libc-2.5.so)
==18523== by 0x4004C7: main (test.c:11)
==18523== Uninitialised value was created by a stack allocation
==18523== at 0x400498: main (test.c:6)
==18523==
==18523== Conditional jump or move depends on uninitialised value(s)
==18523== at 0x3FF8441E37: _itoa_word (in /lib64/libc-2.5.so)
==18523== by 0x3FF8445212: vfprintf (in /lib64/libc-2.5.so)
==18523== by 0x3FF844D009: printf (in /lib64/libc-2.5.so)
==18523== by 0x4004C7: main (test.c:11)
==18523== Uninitialised value was created by a stack allocation
==18523== at 0x400498: main (test.c:6)
==18523==
==18523== Conditional jump or move depends on uninitialised value(s)
==18523== at 0x3FF8445298: vfprintf (in /lib64/libc-2.5.so)
==18523== by 0x3FF844D009: printf (in /lib64/libc-2.5.so)
==18523== by 0x4004C7: main (test.c:11)
==18523== Uninitialised value was created by a stack allocation
==18523== at 0x400498: main (test.c:6)
==18523==
==18523== Conditional jump or move depends on uninitialised value(s)
==18523== at 0x3FF8445AA6: vfprintf (in /lib64/libc-2.5.so)
==18523== by 0x3FF844D009: printf (in /lib64/libc-2.5.so)
==18523== by 0x4004C7: main (test.c:11)
==18523== Uninitialised value was created by a stack allocation
==18523== at 0x400498: main (test.c:6)
==18523==
==18523== Conditional jump or move depends on uninitialised value(s)
==18523== at 0x3FF8443949: vfprintf (in /lib64/libc-2.5.so)
==18523== by 0x3FF844D009: printf (in /lib64/libc-2.5.so)
==18523== by 0x4004C7: main (test.c:11)
==18523== Uninitialised value was created by a stack allocation
==18523== at 0x400498: main (test.c:6)
==18523==
I am 0 inches tall.
==18523==
==18523== HEAP SUMMARY:
==18523== in use at exit: 0 bytes in 0 blocks
==18523== total heap usage: 0 allocs, 0 frees, 0 bytes allocated
==18523==
==18523== All heap blocks were freed -- no leaks are possible
==18523==
==18523== For counts of detected and suppressed errors, rerun with: -v
==18523== ERROR SUMMARY: 5 errors from 5 contexts (suppressed: 7 from 7)
修改： 使用-Wall不会编译此程序，因为它有警告。这意味着编译时不会使用CFLAGS。
尝试按以下方式更改yor makefile：
CFLAGS= -g
TARGET = ex4
ex4: $(TARGET)
$(TARGET): $(TARGET).c
$(CC) $(CFLAGS) -o $(TARGET) $(TARGET).c
clean:
rm -rf ex4
使用上面的makefile对我有用。谷歌有关makefile的了解更多。
答案 1 :(得分：0)
我可以通过向-fno-omit-frame-pointer添加CFLAGS来解决此问题。