PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |

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SQRT(3P) POSIX Programmer's Manual SQRT(3P)
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This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. delim $$

sqrt, sqrtf, sqrtl — square root function

#include <math.h> double sqrt(doublex); float sqrtf(floatx); long double sqrtl(long doublex);

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 POSIX.1‐2008 defers to the ISO C standard. These functions shall compute the square root of their argumentx, $sqrt {x}$. An application wishing to check for error situations should seterrnoto zero and callfeclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, iferrnois non-zero orfetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.

Upon successful completion, these functions shall return the square root ofx. For finite values ofx< −0, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned. Ifxis NaN, a NaN shall be returned. Ifxis ±0 or +Inf,xshall be returned. Ifxis −Inf, a domain error shall occur, and a NaN shall be returned.

These functions shall fail if: Domain Error The finite value ofxis < −0, orxis −Inf. If the integer expression (math_errhandling& MATH_ERRNO) is non-zero, thenerrnoshall 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.

Taking the Square Root of 9.0#include <math.h>...double x = 9.0;double result;...result = sqrt(x);

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.

None.

None.

feclearexcept(3p), fetestexcept(3p), isnan(3p) The Base Definitions volume of POSIX.1‐2008,Section 4.19,Treatmentof Error Conditions for Mathematical Functions, math.h(0p), stdio.h(0p)

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Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 SQRT(3P)
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Pages that refer to this page: math.h(0p), atan2(3p), hypot(3p)