sqrt() gnu C编译出错

RaisingHeart

源代码assert.c:

1. 
   
2. #include <stdio.h>
   
3. #include <math.h>
   
4. #include <stdlib.h>
   
5. #include <assert.h>
   
6. 
   
7. double my_sqrt(double x)
   
8. {
   
9.         assert(x >= 0.0);
   
10.         return sqrt(x);
    
11. }
    
12. 
    
13. int main()
    
14. {
    
15.         printf("sqrt +2 = %g\n", my_sqrt(2.0));
    
16.         printf("sqrt -2 = %g\n", my_sqrt(-2.0));
    
17.         exit(0);
    
18. }
    

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编译过程:

1. 
   
2. [zxz@localhost chapter10]$ gcc -Wall -o assert assert.c
   
3. /tmp/ccGnOiR2.o(.text+0x45): In function `my_sqrt':
   
4. assert.c: undefined reference to `sqrt'
   
5. collect2: ld 返回 1
   
6. [zxz@localhost chapter10]$
   

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书上的例子啊,何解?

soloforce

gcc -Wall -lm -o assert assert.c

RaisingHeart

Post by Lolita
gcc -Wall -lm -o assert assert.c

谢谢,学习学习.