abs-labs-llabs-abs64.md

title	abs, labs, llabs, _abs64
description	API reference for abs, labs, llabs, and _abs64; which calculates the absolute value of a value.
ms.date	04/05/2018
api_name	abs _abs64 labs llabs
api_location	msvcrt.dll msvcr80.dll msvcr90.dll msvcr100.dll msvcr100_clr0400.dll msvcr110.dll msvcr110_clr0400.dll msvcr120.dll msvcr120_clr0400.dll ucrtbase.dll api-ms-win-crt-utility-l1-1-0.dll
api_type	DLLExport
topic_type	apiref
f1_keywords	_abs64 STDLIB/_abs64 abs CORECRT_MATH/abs STDLIB/abs CSTDLIB/abs labs CORECRT_MATH/labs llabs CORECRT_MATH/llabs
helpviewer_keywords	absolute values abs function abs64 function _abs64 function calculating absolute values

abs, labs, llabs, _abs64

Calculates the absolute value of the argument.

Syntax

int abs( int n );
long labs( long n );
long long llabs( long long n );
__int64 _abs64( __int64 n );

long abs( long n );   // C++ only
long long abs( long long n );   // C++ only
double abs( double n );   // C++ only
long double abs( long double n );   // C++ only
float abs( float n );   // C++ only

Parameters

n
Numeric value.

Return value

The abs, labs, llabs, and _abs64 functions return the absolute value of the parameter n. There's no error return.

Remarks

Because C++ allows overloading, you can call overloads of abs that take and return long, long long, float, double, and long double values. These overloads are defined in the <cmath> header. In a C program, abs always takes and returns an int.

Microsoft-specific: The range of negative integers representable in any integral type is larger than the range of positive integers representable in that type. So, it's possible to supply an argument to these functions that can't be converted. If the absolute value of the argument can't be represented by the return type, the abs functions return the argument value unchanged. Specifically, abs(INT_MIN) returns INT_MIN, labs(LONG_MIN) returns LONG_MIN, llabs(LLONG_MIN) returns LLONG_MIN, and _abs64(_I64_MIN) returns _I64_MIN. Effectively, the abs functions can't be used to guarantee a positive value.

Requirements

Routine	Required C header	Required C++ header
abs, labs, llabs	<math.h> or <stdlib.h>	<cmath>, <cstdlib>, <stdlib.h> or <math.h>
_abs64	<stdlib.h>	<cstdlib> or <stdlib.h>

To use the overloaded versions of abs in C++, you must include the <cmath> header.

Example

This program computes and displays the absolute values of several numbers.

// crt_abs.c
// Build: cl /W3 /TC crt_abs.c
// This program demonstrates the use of the abs function
// by computing and displaying the absolute values of
// several numbers.

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <limits.h>

int main( void )
{
    int ix = -4;
    long lx = -41567L;
    long long llx = -9876543210LL;
    __int64 wx = -1;

    // absolute 32 bit integer value
    printf_s("The absolute value of %d is %d\n", ix, abs(ix));

    // absolute long integer value
    printf_s("The absolute value of %ld is %ld\n", lx, labs(lx));

    // absolute long long integer value
    printf_s("The absolute value of %lld is %lld\n", llx, llabs(llx));

    // absolute 64 bit integer value
    printf_s("The absolute value of 0x%.16I64x is 0x%.16I64x\n", wx,
        _abs64(wx));

    // Integer error cases:
    printf_s("Microsoft implementation-specific results:\n");
    printf_s(" abs(INT_MIN) returns %d\n", abs(INT_MIN));
    printf_s(" labs(LONG_MIN) returns %ld\n", labs(LONG_MIN));
    printf_s(" llabs(LLONG_MIN) returns %lld\n", llabs(LLONG_MIN));
    printf_s(" _abs64(_I64_MIN) returns 0x%.16I64x\n", _abs64(_I64_MIN));
}

The absolute value of -4 is 4
The absolute value of -41567 is 41567
The absolute value of -9876543210 is 9876543210
The absolute value of 0xffffffffffffffff is 0x0000000000000001
Microsoft implementation-specific results:
abs(INT_MIN) returns -2147483648
labs(LONG_MIN) returns -2147483648
llabs(LLONG_MIN) returns -9223372036854775808
_abs64(_I64_MIN) returns 0x8000000000000000

See also

Data conversion
Math and floating-point support
_cabs
fabs, fabsf, fabsl
imaxabs