问题描述
我在Ubuntu上尝试一些代码。我正在尝试运行以下代码
#include <cstdlib>
#include <cmath>
#include <ctime>
#include "random.h"
using namespace std;
/* Function prototype! */
void initRandomSeed();
int randomInteger(int low,int high){
initRandomSeed();
double d= rand()/(double(RAND_MAX)+1);
double s= d*(double(high)-low+1);
return int(floor(low)+s);
}
double randomReal(int low,int high){
initRandomSeed();
double d=rand()/(double(RAND_MAX)+1);
double s=d*(double(high)-low+1);
return low+s;
}
bool randomChance(double p){
initRandomSeed();
return randomReal(0,1)<p;
}
void setRandomSeed(int seed){
initRandomSeed();
srand(seed);
}
void initRandomSeed(){
// to retain updated values across different stack frames! nice!
static bool initialized=false;
// this is executed only very first time and random value obtained from system clock!
if(!initialized){
srand(int(time(NULL)));
initialized=true;
}
}
当我尝试使用g++
编译上面的代码时,我收到以下错误
@ubuntu:~/Chardway$ g++ random.cpp
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 0 has invalid symbol index 10
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 1 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 2 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 3 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 4 has invalid symbol index 10
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 5 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 6 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 7 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 8 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 9 has invalid symbol index 2
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 10 has invalid symbol index 11
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 11 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 12 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 13 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 14 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 15 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 16 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 17 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 18 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 19 has invalid symbol index 12
/usr/bin/ld: /usr/lib/debug/usr/lib/x86_64-linux-gnu/crt1.o(.debug_info): relocation 20 has invalid symbol index 19
/usr/lib/gcc/x86_64-linux-gnu/4.6/../../../x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: ld returned 1 exit status
任何帮助或链接到有用的问题将是非常有帮助的!谢谢!
最佳解决办法
我不确定你的无效重定位错误,但显而易见的是你没有main
函数。您需要为应用程序定义一个名为main
的入口点,该入口点在全局范围内定义,例如:
int main()
{
// TODO: implementation
}
次佳解决办法
“对’main’的未定义引用”是因为您没有定义main()
函数,它是程序的入口点:
int main()
{
// call other functions
}
第三种解决办法
有趣的是,如果我尝试编译.h
文件而不是.c
文件,并在一步中链接到库,我会得到相同的错误。
这是一个大大减少的例子:
$ echo 'int main () {}' > test.h
$ g++ test.h -ltommath && echo success
/usr/lib/gcc/x86_64-linux-gnu/4.8/../../../x86_64-linux-gnu/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status
在这种情况下,解决方案是将文件重命名为以.c
结尾:
$ echo 'int main () {}' > test.c
$ g++ test.c -ltommath && echo success
success
第四种办法
当我在gtest中链接到CMake并包含一个包含main函数的文件时,我只是面对同样的事情。
所以,如果你确定你有一个主要的,并且你要链接一些东西 – 确保你没有两个int main()
!
简单的解决方案是将 main()拆分为main.cpp,而不是将其与测试源链接。