Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

expf(3) [posix man page]

EXP(P)							     POSIX Programmer's Manual							    EXP(P)

NAME
exp, expf, expl - exponential function SYNOPSIS
#include <math.h> double exp(double x); float expf(float x); long double expl(long double x); DESCRIPTION
These functions shall compute the base- e exponential of 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 exponential value of x. If the correct value would cause overflow, a range error shall occur and exp(), expf(), and expl() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively. If the correct value would cause underflow, and is not representable, a range error may occur, and either 0.0 (if supported), or an implementation-defined value shall be returned. If x is NaN, a NaN shall be returned. If x is +-0, 1 shall be returned. If x is -Inf, +0 shall be returned. If x is +Inf, x shall be returned. If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be returned. ERRORS
These functions shall fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised. These functions may fail if: Range Error The result underflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
Note that for IEEE Std 754-1985 double, 709.8 < x implies exp( x) has overflowed. The value x < -708.4 implies exp( x) has underflowed. 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. SEE ALSO
feclearexcept() , fetestexcept() , isnan() , log() , the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathematical Functions, <math.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- 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 . IEEE
/The Open Group 2003 EXP(P)

Check Out this Related Man Page

EXP(3P) 						     POSIX Programmer's Manual							   EXP(3P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
exp, expf, expl - exponential function SYNOPSIS
#include <math.h> double exp(double x); float expf(float x); long double expl(long double x); DESCRIPTION
These functions shall compute the base- e exponential of 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 exponential value of x. If the correct value would cause overflow, a range error shall occur and exp(), expf(), and expl() shall return the value of the macro HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively. If the correct value would cause underflow, and is not representable, a range error may occur, and either 0.0 (if supported), or an imple- mentation-defined value shall be returned. If x is NaN, a NaN shall be returned. If x is +-0, 1 shall be returned. If x is -Inf, +0 shall be returned. If x is +Inf, x shall be returned. If the correct value would cause underflow, and is representable, a range error may occur and the correct value shall be returned. ERRORS
These functions shall fail if: Range Error The result overflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised. These functions may fail if: Range Error The result underflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the underflow floating-point exception shall be raised. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
Note that for IEEE Std 754-1985 double, 709.8 < x implies exp( x) has overflowed. The value x < -708.4 implies exp( x) has underflowed. 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. SEE ALSO
feclearexcept(), fetestexcept(), isnan(), log(), the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Con- ditions for Mathematical Functions, <math.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- 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 . IEEE
/The Open Group 2003 EXP(3P)
Man Page