Ubuntu Bash 上 windows 上的 gcc 问题与数学库
Issue with gcc on Ubuntu Bash on windows with math library
我有一个使用“-lm”标志来包含数学库的生成文件。我还为每个 .c 文件包含了#include。
我仍然遇到错误和 "undefined reference" 数学运算，例如 exp、floor 和 pow 等
在 windows Ubuntu 上使用 bash。
我的终端输出的副本：
labyu@DESKTOP-U037B9F:~/software/BICseq2/NBICseq-norm_v0.2.4$ make
gcc -g -O2 -Wall -lm -c -o combineFile/combine.o combineFile/combine.c
gcc -g -O2 -Wall -lm -c -o lib/read.o lib/read.c
lib/read.c: In function ‘read_table’:
lib/read.c:74:14: warning: variable ‘flag’ set but not used [-Wunused-but-set-variable]
int i=0,j=0,flag=1,low_mmry = 40000, is_num=0,k;
^
gcc -g -O2 -Wall -lm combineFile/combine.o lib/read.o -o combineFile/combineFile
gcc -g -O2 -Wall -lm -c -o DataPrepare/DtaPrep.o DataPrepare/DtaPrep.c
gcc -g -O2 -Wall -lm -c -o lib/statlib.o lib/statlib.c
gcc -g -O2 -Wall -lm DataPrepare/DtaPrep.o lib/read.o lib/statlib.o -o DataPrepare/PrepPois
DataPrepare/DtaPrep.o: In function `print_oneline':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:593: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:591: undefined reference to `log'
DataPrepare/DtaPrep.o: In function `calculate_bias':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:685: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:690: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:681: undefined reference to `log'
DataPrepare/DtaPrep.o: In function `fprint_gc_bin':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:810: undefined reference to `floor'
DataPrepare/DtaPrep.o: In function `fprintf_predicted':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:850: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:860: undefined reference to `floor'
DataPrepare/DtaPrep.o: In function `calculate_bias':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:749: undefined reference to `exp'
lib/statlib.o: In function `db_shuffle':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:56: undefined reference to `floor'
lib/statlib.o: In function `db_shuffle_int':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:71: undefined reference to `floor'
lib/statlib.o: In function `rgamma1':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:99: undefined reference to `log'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:100: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:103: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:104: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:90: undefined reference to `log'
collect2: error: ld returned 1 exit status
make: *** [PrepPois] Error 1
但是，当我制作一个示例程序时，例如：test.c
#include <stdio.h>
#include <math.h>
int main(void)
{
int number;
number = pow(10,2);
printf("%d\n", number);
return 0;
}
即使没有 -lm 标志，我也可以使用 gcc test.c，并且编译正常。
这是一个错误吗？
在您的测试用例中，由于所有数据都是常量，因此编译器似乎直接计算了值（这可能取决于编译器，但最新版本的 gcc 似乎可以很好地处理这个问题）
反汇编代码(x86)的时候看的一清二楚
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 83 ec 30 sub [=10=]x30,%rsp
8: e8 00 00 00 00 callq d <main+0xd>
direct 100 value passed to printf at the line below
d: c7 45 fc 64 00 00 00 movl [=11=]x64,-0x4(%rbp)
14: 8b 45 fc mov -0x4(%rbp),%eax
17: 89 c2 mov %eax,%edx
19: 48 8d 0d 00 00 00 00 lea 0x0(%rip),%rcx # 20 <main+0x20>
20: e8 00 00 00 00 callq 25 <main+0x25>
25: b8 00 00 00 00 mov [=11=]x0,%eax
2a: 90 nop
2b: 48 83 c4 30 add [=11=]x30,%rsp
2f: 5d pop %rbp
30: c3 retq
31: 90 nop
我已将代码更改为：
#include <stdio.h>
#include <math.h>
int main(void)
{
int number;
int v=10;
number = pow(v,2);
printf("%d\n", number);
return 0;
}
现在，当我 nm 文件时，我得到：
>nm simplemath.o
0000000000000000 b .bss
0000000000000000 d .data
0000000000000000 p .pdata
0000000000000000 r .rdata
0000000000000000 r .rdata$zzz
0000000000000000 t .text
0000000000000000 r .xdata
U __main
0000000000000000 T main
U pow
U printf
在我引入变量之前，没有引用pow符号。编译器静态计算。
反汇编显示了更复杂的代码，使用浮点寄存器和所有。
0000000000000000 <main>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 83 ec 40 sub [=14=]x40,%rsp
8: e8 00 00 00 00 callq d <main+0xd>
d: c7 45 fc 0a 00 00 00 movl [=14=]xa,-0x4(%rbp)
14: 66 0f ef c0 pxor %xmm0,%xmm0
18: f2 0f 2a 45 fc cvtsi2sdl -0x4(%rbp),%xmm0
1d: 48 b8 00 00 00 00 00 movabs [=14=]x4000000000000000,%rax
24: 00 00 40
27: 48 89 45 e8 mov %rax,-0x18(%rbp)
2b: f2 0f 10 4d e8 movsd -0x18(%rbp),%xmm1
30: e8 00 00 00 00 callq 35 <main+0x35> <== the linker wil add the call to pow here
35: f2 0f 2c c0 cvttsd2si %xmm0,%eax
39: 89 45 f8 mov %eax,-0x8(%rbp)
3c: 8b 45 f8 mov -0x8(%rbp),%eax
3f: 89 c2 mov %eax,%edx
41: 48 8d 0d 00 00 00 00 lea 0x0(%rip),%rcx # 48 <main+0x48>
48: e8 00 00 00 00 callq 4d <main+0x4d>
4d: b8 00 00 00 00 mov [=14=]x0,%eax
52: 90 nop
53: 48 83 c4 40 add [=14=]x40,%rsp
57: 5d pop %rbp
58: c3 retq
但令我惊讶的是，不需要 -lm，没有它也可以链接。
最新的 gcc 版本必须默认包含它，因为它经常被使用。也许有人可以确认。你的版本似乎需要它，我的不需要 (gcc 4.9.4)
我有一个使用“-lm”标志来包含数学库的生成文件。我还为每个 .c 文件包含了#include。 我仍然遇到错误和 "undefined reference" 数学运算，例如 exp、floor 和 pow 等
在 windows Ubuntu 上使用 bash。
我的终端输出的副本：
labyu@DESKTOP-U037B9F:~/software/BICseq2/NBICseq-norm_v0.2.4$ make
gcc -g -O2 -Wall -lm -c -o combineFile/combine.o combineFile/combine.c
gcc -g -O2 -Wall -lm -c -o lib/read.o lib/read.c
lib/read.c: In function ‘read_table’:
lib/read.c:74:14: warning: variable ‘flag’ set but not used [-Wunused-but-set-variable]
int i=0,j=0,flag=1,low_mmry = 40000, is_num=0,k;
^
gcc -g -O2 -Wall -lm combineFile/combine.o lib/read.o -o combineFile/combineFile
gcc -g -O2 -Wall -lm -c -o DataPrepare/DtaPrep.o DataPrepare/DtaPrep.c
gcc -g -O2 -Wall -lm -c -o lib/statlib.o lib/statlib.c
gcc -g -O2 -Wall -lm DataPrepare/DtaPrep.o lib/read.o lib/statlib.o -o DataPrepare/PrepPois
DataPrepare/DtaPrep.o: In function `print_oneline':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:593: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:591: undefined reference to `log'
DataPrepare/DtaPrep.o: In function `calculate_bias':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:685: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:690: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:681: undefined reference to `log'
DataPrepare/DtaPrep.o: In function `fprint_gc_bin':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:810: undefined reference to `floor'
DataPrepare/DtaPrep.o: In function `fprintf_predicted':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:850: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:860: undefined reference to `floor'
DataPrepare/DtaPrep.o: In function `calculate_bias':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/DataPrepare/DtaPrep.c:749: undefined reference to `exp'
lib/statlib.o: In function `db_shuffle':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:56: undefined reference to `floor'
lib/statlib.o: In function `db_shuffle_int':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:71: undefined reference to `floor'
lib/statlib.o: In function `rgamma1':
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:99: undefined reference to `log'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:100: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:103: undefined reference to `pow'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:104: undefined reference to `exp'
/home/labyu/software/BICseq2/NBICseq-norm_v0.2.4/lib/statlib.c:90: undefined reference to `log'
collect2: error: ld returned 1 exit status
make: *** [PrepPois] Error 1
但是，当我制作一个示例程序时，例如：test.c
#include <stdio.h>
#include <math.h>
int main(void)
{
int number;
number = pow(10,2);
printf("%d\n", number);
return 0;
}
即使没有 -lm 标志，我也可以使用 gcc test.c，并且编译正常。
这是一个错误吗？
在您的测试用例中，由于所有数据都是常量，因此编译器似乎直接计算了值（这可能取决于编译器，但最新版本的 gcc 似乎可以很好地处理这个问题）
反汇编代码(x86)的时候看的一清二楚
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 83 ec 30 sub [=10=]x30,%rsp
8: e8 00 00 00 00 callq d <main+0xd>
direct 100 value passed to printf at the line below
d: c7 45 fc 64 00 00 00 movl [=11=]x64,-0x4(%rbp)
14: 8b 45 fc mov -0x4(%rbp),%eax
17: 89 c2 mov %eax,%edx
19: 48 8d 0d 00 00 00 00 lea 0x0(%rip),%rcx # 20 <main+0x20>
20: e8 00 00 00 00 callq 25 <main+0x25>
25: b8 00 00 00 00 mov [=11=]x0,%eax
2a: 90 nop
2b: 48 83 c4 30 add [=11=]x30,%rsp
2f: 5d pop %rbp
30: c3 retq
31: 90 nop
我已将代码更改为：
#include <stdio.h>
#include <math.h>
int main(void)
{
int number;
int v=10;
number = pow(v,2);
printf("%d\n", number);
return 0;
}
现在，当我 nm 文件时，我得到：
>nm simplemath.o
0000000000000000 b .bss
0000000000000000 d .data
0000000000000000 p .pdata
0000000000000000 r .rdata
0000000000000000 r .rdata$zzz
0000000000000000 t .text
0000000000000000 r .xdata
U __main
0000000000000000 T main
U pow
U printf
在我引入变量之前，没有引用pow符号。编译器静态计算。
反汇编显示了更复杂的代码，使用浮点寄存器和所有。
0000000000000000 <main>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 83 ec 40 sub [=14=]x40,%rsp
8: e8 00 00 00 00 callq d <main+0xd>
d: c7 45 fc 0a 00 00 00 movl [=14=]xa,-0x4(%rbp)
14: 66 0f ef c0 pxor %xmm0,%xmm0
18: f2 0f 2a 45 fc cvtsi2sdl -0x4(%rbp),%xmm0
1d: 48 b8 00 00 00 00 00 movabs [=14=]x4000000000000000,%rax
24: 00 00 40
27: 48 89 45 e8 mov %rax,-0x18(%rbp)
2b: f2 0f 10 4d e8 movsd -0x18(%rbp),%xmm1
30: e8 00 00 00 00 callq 35 <main+0x35> <== the linker wil add the call to pow here
35: f2 0f 2c c0 cvttsd2si %xmm0,%eax
39: 89 45 f8 mov %eax,-0x8(%rbp)
3c: 8b 45 f8 mov -0x8(%rbp),%eax
3f: 89 c2 mov %eax,%edx
41: 48 8d 0d 00 00 00 00 lea 0x0(%rip),%rcx # 48 <main+0x48>
48: e8 00 00 00 00 callq 4d <main+0x4d>
4d: b8 00 00 00 00 mov [=14=]x0,%eax
52: 90 nop
53: 48 83 c4 40 add [=14=]x40,%rsp
57: 5d pop %rbp
58: c3 retq
但令我惊讶的是，不需要 -lm，没有它也可以链接。
最新的 gcc 版本必须默认包含它，因为它经常被使用。也许有人可以确认。你的版本似乎需要它，我的不需要 (gcc 4.9.4)