未定义参考`sin` [英] Undefined reference to `sin`

问题描述

我有以下的code（精简裸基础知识这个问题）：

I have the following code (stripped down to the bare basics for this question):

#include<stdio.h>
#include<math.h>

double f1(double x)
{
    double res = sin(x);
    return 0;
}

/* The main function */
int main(void)
{
    return 0;
}

在与编译它海合会test.c以我碰到下面的错误，我不能工作了原因：

When compiling it with gcc test.c I get the following error, and I can't work out why:

/tmp/ccOF5bis.o: In function `f1':
test2.c:(.text+0x13): undefined reference to `sin'
collect2: ld returned 1 exit status

不过，我已经写了调用各种测试程序罪从主函数中，而那些工作完美。我必须明明在这里做得不对？ - 但它是什么

However, I've written various test programs that call sin from within the main function, and those work perfectly. I must be doing something obviously wrong here - but what is it?

推荐答案

您已经编译了code与正确math.h中头文件的引用，但是当你试图连接它，你忘了选择包括数学库。这样一来，就可以编译.o目标文件，但不建立自己的可执行文件。

You have compiled your code with references to the correct math.h header file, but when you attempted to link it, you forgot the option to include the math library. As a result, you can compile your .o object files, but not build your executable.

由于保罗已经提到添加-lm，包括在您正试图生成可执行步骤的数学库。

As Paul has already mentioned add "-lm" to include the math library in the step where you are attempting to generate your executable.

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