linux-程序手冊之sqrt

SQRT(3)                    Linux Programmer's Manual                   SQRT(3)
sqrt(3)                         linux程序手冊

NAME

mane：名字

       sqrt,  sqrtf,  sqrtl    - square root function（平方根函數）

SYNOPSIS

synopsis:概要、大綱

       #include <math.h>

       double sqrt(double x);

       float     sqrtf(float x);

       long double sqrtl(long double x);


       Link with -lm.   ：用 -lm 連接。


   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

            sqrtf(), sqrtl():

           _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
           or cc -std=c99

DESCRIPTION

description：描述

       The sqrt() function returns the nonnegative square root of x.

意思是這個sqrt（）函數將會返回一個整數的x

RETURN VALUE

返回值

       On success, these functions return the square root of x.

       If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.


       If x is positive infinity,     positive infinity is returned.


       If x is less than -0, a domain error occurs, and a NaN is returned.


ERRORS

錯誤：負數就會報錯
       See math_error(7) for information on how to determine whether an  error
       has occurred when calling these functions.


       The following errors can occur:


       Domain error: x less than -0
              errno  is  set  to  EDOM.   An  invalid floating-point exception
              (FE_INVALID) is raised.


CONFORMING TO

conforming to：遵守於
       C99, POSIX.1-2001.  The variant returning double also conforms to SVr4,
       4.3BSD, C89.


SEE ALSO

另請參考：
       cbrt(3), csqrt(3), hypot(3)


COLOPHON

colophon：其他記載
       This  page  is  part of release 3.54 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

例子：

hank@ubuntu:/mnt/hgfs/Pictures$       gcc test.c -lm