令人不安的阵营（我认为）问题。 [英] Troubling Alignment (I think) issue.
问题描述
对齐问题我有。希望我能通过下面的代码解释这个最好的
。下面的ACSign和MyACSign函数被编译成一个库，其中执行这些
函数的代码被编译成一个单独的库。打电话到MyACSign
工作正常，直接ACSign的电话没有，我相信这是对齐问题，但我不能指出如何。这< i>应该< / ihave
非常基本。任何帮助当然非常感谢，
- Kevin
功能代码：
********* ***************************************** ********* *********
双ACSign（双倍）{
if（a 0.0）
return（1.0）;
else if（a< 0.0）
return（-1.0）;
}
double * MyACSign（double * a）{
if（* a 0.0）
* a = 1.0;
else if（* a < 0.0）
* a = -1.0;
返回a;
}
执行代码：
*************************************** *********** ******************
double test = 0;
double test1 = 0;
test = 0.707107;
test1 = test * -1;
printf（" Locations： ％u，％u \\\\ n"，& test，& test1）;
printf（" 0Double：％f，％f"，test，test1 ）;
printf（" 1Double：％f，％f"，ACSign（test），ACSign（test1））;
printf（" 2Double：％i，％i"，（char）ACSign（test），（char）ACSign（test1））;
printf（" 3Double：％f ，％f"，0.707107，-0.707107）;
printf（" 4Double：％f，％f"，ACSign（0.707107），ACSign（-0.707107））;
printf（" 5Double：％i，％i"，（char）ACSign（0.707107），
（char）ACSign（-0.707107））;
printf（" 6Double：％f，％f"，test，test1）;
printf（" 7Double：％f，％f"，*（double *）MyACSign（& ;测试），
*（double *）MyACSign（& test1））;
printf（" 8Double：％i，％i"，（char）* （double *）MyACSign（& test），
（char）*（double *）MyACSign（& test1））;
******* ******************************************* ******* ***********
我得到的输出是：
地点：4263558272,4263558264
0Double：0.707107， -0.707107
1Double：0.707107，-0.707107
2Double：-98，-98
3Double：0.707107，-0.707107
4Doub le：0.707107,0.000000
5Double：-98，-98
6Double：0.707107，-0.707107
7Double：1.000000，-1.000000
8Double：1，-1
Kevin< ke ******** @ gmail.com写的：
嘿，我希望有人在这里可能能够解决一些
对齐问题我''我有。
我怀疑你的问题与对齐有什么关系。
相反，我怀疑你没有正确宣布
函数在头文件中，例如
double ACSign（double）;
double * MyACSign（double *）;
原型（括号中的位）是可选的，但是它们可以帮助编译器检查调用。
-
char a [] = " \ n .CJacehknorstu" ;; int putchar（int）; int main（void）{unsigned long b []
= {0x67dffdff，0x9aa9aa6a，0xa77ffda9,0x7da6aa6a，0xa6 7f6aaa，0xaa9aa9f6,0x11f6 }，* p
= b，i = 24; for（; p + =！* p; * p / = 4）switch（0 [p]& 3）case 0：{return 0 ; for（p - ; i - ; i - ）case +
2：{i ++; if（i）break; else default：continue; if（0）case 1：putchar（a [i& 15]）; break;}}}
2007年11月7日星期三上午1:57 Kevin< ke ******** @ gmail .comwrote在
文章< 11 ********************** @ i38g2000prf.googlegroups .com>：
< blockq uote class =post_quotes>
嘿，我希望有人在这里可能能够让我知道一些
对齐问题。希望我能通过下面的代码解释这个最好的
。下面的ACSign和MyACSign函数被编译成一个库，其中执行这些
函数的代码被编译成一个单独的库。打电话到MyACSign
工作正常，直接ACSign的电话没有，我相信这是对齐问题，但我不能指出如何。这< i>应该< / ihave
非常基本。任何帮助当然非常感谢，
- Kevin
功能代码：
***** ********************************************* ***** *************
双ACSign（双倍）{
如果（a 0.0）
返回（1.0）;
括号和小数点都是不必要的。
else if（a< 0.0）
return（-1.0）;
同样在这里。
}
double * MyACSign（double * a）{
if（* a 0.0）
* a = 1.0;
else if（* a< 0.0 ）
* a = -1.0;
返回a;
}
执行代码：
****************************************** ******** ******************
double test = 0;
double test1 = 0;
test = 0.707107;
test1 = test * -1;
printf（"地点：％u， ％u \\\\ n"，& test，& test1）;
编号要打印指针，请使用''％p''说明符并将相应的
参数转换为void *。此外，''\ r''不仅没有必要，而且可能会导致问题。 C标准库将''\ n''转换为系统用作行尾的
。
printf （0Double：％f，％f，test，test1）;
printf（" 1Double：％f，％f"，ACSign（test），ACSign（test1））;
printf（" 2Double：％i，％i"，（char）ACSign（test），（char）ACSign（test1））;
将一个double值转换为char然后在告诉它看起来后将它们正确传递给printf的重点是什么？对于一个int？使用
''％c''格式打印字符。
printf（" 3Double：％f，％f" ，0.707107，-0.707107）;
printf（" 4Double：％f，％f"，ACSign（0.707107），ACSign（-0.707107））;
printf（ 5Double：％i，％i，（char）ACSign（0.707107），
再次出现相同的问题。除了你有望看到有损后的什么
cast？
（char）ACSign（-0.707107））;
printf（" ; 6Double：％f，％f"，test，test1）;
printf（" 7Double：％f，％f"，*（double *）MyACSign（& test），
编号使用*（MyACSign（& test））。
*（double *）MyACSign（ &安培; TEST1））;
同样。
printf（" 8Double：％i，％i"，（char） *（double *）MyACSign（& test），
（char）*（double *）MyACSign（& test1））;
再次将这个神秘的强制转换为char值。
********* ***************************************** ********* *********
我得到的输出是：
地点：4263558272,4263558264
0Double：0.707107，-0.707107
1Double：0.707107，-0.707107
2Double：-98，-98
3Double：0.707107，-0.707107
4Double：0.707107,0.000000
5Double：-98，-98
6Double：0.707107，-0.707107
7Double：1.000000，-1.000000
8Double：1，-1
由于您在多个地方调用了未定义的行为，您可以获得
any一种输出。我建议你修复明显的错误并重新编译
并重新运行。
Bingo，我偶然发现同样的答案时间 - 谢谢！我在编译代码中错过了隐含的声明警告，我的
合作伙伴错过了标题中的这一项功能。
谢谢再次！
- Kevin
11月6日下午3:37，Ben Pfaff< b ... @ cs.stanford.eduwrote：
Kevin< kevinwo ... @ gmail.comwrites：
嘿，我希望有人在这里或许可以让我知道我正在讨论的一些问题。
我怀疑你的问题与对齐有什么关系。
相反，我怀疑你没有正确宣布
函数在头文件中，例如
double ACSign（double）;
double * MyACSign（double *）;
原型（括号中的位）是可选的，但是它们可以帮助编译器检查调用。
-
char a [] = " \ n .CJacehknorstu" ;; int putchar（int）; int main（void）{unsigned long b []
= {0x67dffdff，0x9aa9aa6a，0xa77ffda9,0x7da6aa6a，0xa6 7f6aaa，0xaa9aa9f6,0x11f6 } *，* p
= b，i = 24; for（; p + =！* p; * p / = 4）switch（0 [p]& 3）case 0：{return 0; for（p - ; i - ; i - ）case +
2：{i ++; if（i）break; else default：continue; if（0）case 1：putchar（ a [i& 15]）; break;}}}
Hey, I was hoping someone out here might be able to clue me in on some
alignment issues I''m having. Hopefully I can explain this best
through code below. ACSign and MyACSign functions below get compiled
(gcc) into one library, where as the code that executes these
functions gets compiled into a seperate library. Calls to MyACSign
work fine, calls to the straight ACSign do not and I believe it is due
to alignment issues, but I can''t pinpoint how. This <i>should</ihave
been very elementary. Any help is of course greatly appreciated,
- Kevin
Function Code:
************************************************** ******************
double ACSign ( double a) {
if (a 0.0)
return(1.0);
else if (a < 0.0)
return(-1.0);
}
double * MyACSign (double * a) {
if (*a 0.0)
*a = 1.0;
else if (*a < 0.0)
*a = -1.0;
return a;
}
Execution Code:
************************************************** ******************
double test = 0 ;
double test1 = 0;
test = 0.707107;
test1 = test * -1;
printf("Locations: %u, %u\r\n", &test, &test1);
printf("0Double: %f, %f", test, test1);
printf("1Double: %f, %f", ACSign(test), ACSign(test1));
printf("2Double: %i, %i", (char)ACSign(test), (char)ACSign(test1));
printf("3Double: %f, %f", 0.707107, -0.707107);
printf("4Double: %f, %f", ACSign(0.707107), ACSign(-0.707107));
printf("5Double: %i, %i", (char)ACSign(0.707107),
(char)ACSign(-0.707107));
printf("6Double: %f, %f", test, test1);
printf("7Double: %f, %f", *(double*)MyACSign(&test),
*(double*)MyACSign(&test1));
printf("8Double: %i, %i", (char)*(double*)MyACSign(&test),
(char)*(double*)MyACSign(&test1));
************************************************** ******************
The output I get is:
Locations: 4263558272, 4263558264
0Double: 0.707107, -0.707107
1Double: 0.707107, -0.707107
2Double: -98, -98
3Double: 0.707107, -0.707107
4Double: 0.707107, 0.000000
5Double: -98, -98
6Double: 0.707107, -0.707107
7Double: 1.000000, -1.000000
8Double: 1, -1
Kevin <ke********@gmail.comwrites:
Hey, I was hoping someone out here might be able to clue me in on some
alignment issues I''m having.I doubt your problems have anything to do with alignment.
Rather, I suspect that you are not properly declaring the
functions in a header file, e.g.
double ACSign(double);
double *MyACSign(double *);
The prototypes (the bits in parentheses) are optional but they
help the compiler to check the calls.
--
char a[]="\n .CJacehknorstu";int putchar(int);int main(void){unsigned long b[]
={0x67dffdff,0x9aa9aa6a,0xa77ffda9,0x7da6aa6a,0xa6 7f6aaa,0xaa9aa9f6,0x11f6},*p
=b,i=24;for(;p+=!*p;*p/=4)switch(0[p]&3)case 0:{return 0;for(p--;i--;i--)case+
2:{i++;if(i)break;else default:continue;if(0)case 1:putchar(a[i&15]);break;}}}
On Wednesday 07 Nov 2007 1:57 am Kevin <ke********@gmail.comwrote in
article <11**********************@i38g2000prf.googlegroups .com>:
Hey, I was hoping someone out here might be able to clue me in on some
alignment issues I''m having. Hopefully I can explain this best
through code below. ACSign and MyACSign functions below get compiled
(gcc) into one library, where as the code that executes these
functions gets compiled into a seperate library. Calls to MyACSign
work fine, calls to the straight ACSign do not and I believe it is due
to alignment issues, but I can''t pinpoint how. This <i>should</ihave
been very elementary. Any help is of course greatly appreciated,
- Kevin
Function Code:
************************************************** ******************
double ACSign ( double a) {
if (a 0.0)
return(1.0);Both the parenthesis and the decimal point are unnecessary.
else if (a < 0.0)
return(-1.0);Similarly here.
}
double * MyACSign (double * a) {
if (*a 0.0)
*a = 1.0;
else if (*a < 0.0)
*a = -1.0;
return a;
}
Execution Code:
************************************************** ******************
double test = 0 ;
double test1 = 0;
test = 0.707107;
test1 = test * -1;
printf("Locations: %u, %u\r\n", &test, &test1);No. To print pointers use the ''%p'' specifier and cast the corresponding
argument to void *. Also the ''\r'' is not only not necessary but may
cause problems. The C Standard library translates a ''\n'' to whatever
the system uses as end-of-line.
printf("0Double: %f, %f", test, test1);
printf("1Double: %f, %f", ACSign(test), ACSign(test1));
printf("2Double: %i, %i", (char)ACSign(test), (char)ACSign(test1));What''s the point in casting a double value to a char and then passing
them inccorrectly to printf after telling it to look for an int? Use
the ''%c'' format to print a char.
printf("3Double: %f, %f", 0.707107, -0.707107);
printf("4Double: %f, %f", ACSign(0.707107), ACSign(-0.707107));
printf("5Double: %i, %i", (char)ACSign(0.707107),Same problems again. Besides what are you expecting to see after a lossy
cast?
(char)ACSign(-0.707107));
printf("6Double: %f, %f", test, test1);
printf("7Double: %f, %f", *(double*)MyACSign(&test),No. Use *(MyACSign(&test)).
*(double*)MyACSign(&test1));Similarly.
printf("8Double: %i, %i", (char)*(double*)MyACSign(&test),
(char)*(double*)MyACSign(&test1));Again this mysterious cast to a char value.
************************************************** ******************
The output I get is:
Locations: 4263558272, 4263558264
0Double: 0.707107, -0.707107
1Double: 0.707107, -0.707107
2Double: -98, -98
3Double: 0.707107, -0.707107
4Double: 0.707107, 0.000000
5Double: -98, -98
6Double: 0.707107, -0.707107
7Double: 1.000000, -1.000000
8Double: 1, -1As you have invoked undefined behaviour in several places you could get
any kind of output. I suggest you fix the obvious errors and recompile
and rerun.
Bingo, I stumbled upon the same answer at the same time - thanks!. I
missed the implied declaration warning in the compiling code and my
partners missed this one function in the header.
Thanks again!
- Kevin
On Nov 6, 3:37 pm, Ben Pfaff <b...@cs.stanford.eduwrote:Kevin <kevinwo...@gmail.comwrites:Hey, I was hoping someone out here might be able to clue me in on some
alignment issues I''m having.
I doubt your problems have anything to do with alignment.
Rather, I suspect that you are not properly declaring the
functions in a header file, e.g.
double ACSign(double);
double *MyACSign(double *);
The prototypes (the bits in parentheses) are optional but they
help the compiler to check the calls.
--
char a[]="\n .CJacehknorstu";int putchar(int);int main(void){unsigned long b[]
={0x67dffdff,0x9aa9aa6a,0xa77ffda9,0x7da6aa6a,0xa6 7f6aaa,0xaa9aa9f6,0x11f6}*,*p
=b,i=24;for(;p+=!*p;*p/=4)switch(0[p]&3)case 0:{return 0;for(p--;i--;i--)case+
2:{i++;if(i)break;else default:continue;if(0)case 1:putchar(a[i&15]);break;}}}
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