linux下调用math.h编译出错undefinde reference to 'sin'

如果直接gcc编译，会出现未定义的情况：

/tmp/ccbS6FZx.o: In function `main':

fft.c:(.text+0x71): undefined reference to `sin'

fft.c:(.text+0x9f): undefined reference to `sin'

fft.c:(.text+0x25e): undefined reference to `pow'

fft.c:(.text+0x2d5): undefined reference to `pow'

fft.c:(.text+0x45e): undefined reference to `pow'

fft.c:(.text+0x548): undefined reference to `sqrt'

/tmp/ccbS6FZx.o: In function `Wn_i':

fft.c:(.text+0x64d): undefined reference to `cos'

fft.c:(.text+0x674): undefined reference to `sin'

collect2: error: ld returned 1 exit status

是因为缺少调用，具体需要添加-lm进行编译

gcc a.c -o a -lm

 其中a.c为源代码，a为编译后输出结果， -lm为gcc选项

在编译即可。