fmin, fminf, fminl

Defined in header <math.h>
float       fminf( float x, float y );
(1) (since C99)
double      fmin( double x, double y );
(2) (since C99)
long double fminl( long double x, long double y );
(3) (since C99)
Defined in header <tgmath.h>
#define fmin( x, y )
(4) (since C99)
1-3) Returns the smaller of two floating point arguments, treating NaNs as missing data (between a NaN and a numeric value, the numeric value is chosen).
4) Type-generic macro: If any argument has type long double, fminl is called. Otherwise, if any argument has integer type or has type double, fmin is called. Otherwise, fminf is called.


x, y - floating point values

Return value

If successful, returns the smaller of two floating point values. The value returned is exact and does not depend on any rounding modes.

Error handling

This function is not subject to any of the error conditions specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),

  • If one of the two arguments is NaN, the value of the other argument is returned
  • Only if both arguments are NaN, NaN is returned


This function is not required to be sensitive to the sign of zero, although some implementations additionally enforce that if one argument is +0 and the other is -0, then -0 is returned.


#include <stdio.h>
#include <math.h>
int main(void)
    printf("fmin(2,1)    = %f\n", fmin(2,1));
    printf("fmin(-Inf,0) = %f\n", fmin(-INFINITY,0));
    printf("fmin(NaN,-1) = %f\n", fmin(NAN,-1));

Possible output:

fmin(2,1)    = 1.000000
fmin(-Inf,0) = -inf
fmin(NaN,-1) = -1.000000


  • C11 standard (ISO/IEC 9899:2011):
    • The fmin functions (p: 258)
    • 7.25 Type-generic math <tgmath.h> (p: 373-375)
    • F.10.9.3 The fmin functions (p: 530)
  • C99 standard (ISO/IEC 9899:1999):
    • The fmin functions (p: 239)
    • 7.22 Type-generic math <tgmath.h> (p: 335-337)
    • F.9.9.3 The fmin functions (p: 466)

See also

checks if the first floating-point argument is less than the second
(function macro)
determines larger of two floating-point values
C++ documentation for fmin

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