Проект OpenNet: MAN sqrtl (3) Библиотечные вызовы (FreeBSD и Linux)

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sqrtl (3)

sqrtl (3) ( Русские man: Библиотечные вызовы )

sqrtl (3) ( Linux man: Библиотечные вызовы )

>> sqrtl (3) ( POSIX man: Библиотечные вызовы )

NAME

sqrt, sqrtf, sqrtl - square root function

SYNOPSIS

#include <math.h>

double sqrt(double x);
float sqrtf(float x);
long double sqrtl(long double x);

DESCRIPTION

The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard.

These functions shall compute the square root of their argument x,

An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

RETURN VALUE

Upon successful completion, these functions shall return the square root of x.

For finite values of x < -0, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.

If x is NaN, a NaN shall be returned.

If x is ±0 or +Inf, x shall be returned.

If x is -Inf, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.

ERRORS

These functions shall fail if:

Domain Error: The finite value of x is < -0, or x is -Inf.

If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised.

The following sections are informative.

EXAMPLES

Taking the Square Root of 9.0


#include <math.h>
...
double x = 9.0;
double result;
...
result = sqrt(x);

APPLICATION USAGE

On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.

RATIONALE

None.

FUTURE DIRECTIONS

None.

COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .