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  12 .TH exp 3M "12 Jul 2006" "SunOS 5.11" "Mathematical Library Functions"
  13 .SH NAME
  14 exp, expf, expl \- exponential function
  15 .SH SYNOPSIS
  16 .LP
  17 .nf
  18 c99 [ \fIflag\fR... ] \fIfile\fR... \fB-lm\fR [ \fIlibrary\fR... ]
  19 #include <math.h>
  20 
  21 \fBdouble\fR \fBexp\fR(\fBdouble\fR \fIx\fR);
  22 .fi
  23 
  24 .LP
  25 .nf
  26 \fBfloat\fR \fBexpf\fR(\fBfloat\fR \fIx\fR);
  27 .fi
  28 
  29 .LP
  30 .nf
  31 \fBlong double\fR \fBexpl\fR(\fBlong double\fR \fIx\fR);
  32 .fi
  33 
  34 .SH DESCRIPTION
  35 .sp
  36 .LP
  37 These functions compute the base-\fIe\fR exponential of \fIx\fR.
  38 .SH RETURN VALUES
  39 .sp
  40 .LP
  41 Upon successful completion, these functions return the exponential value of
  42 \fIx\fR.
  43 .sp
  44 .LP
  45 If the correct value would cause overflow, a range error occurs and
  46 \fBexp()\fR, \fBexpf()\fR, and \fBexpl()\fR return \fBHUGE_VAL\fR,
  47 \fBHUGE_VALF\fR, and \fBHUGE_VALL\fR, respectively.
  48 .sp
  49 .LP
  50 If \fIx\fR is NaN, a NaN is returned.
  51 .sp
  52 .LP
  53 If \fIx\fR is \(+-0, 1 is returned.
  54 .sp
  55 .LP
  56 If \fIx\fR is +Inf, \fIx\fR is returned.
  57 .sp
  58 .LP
  59 For exceptional cases, \fBmatherr\fR(3M) tabulates the values to be returned by
  60 \fBexp()\fR as specified by SVID3 and XPG3. See \fBstandards\fR(5).
  61 .SH ERRORS
  62 .sp
  63 .LP
  64 These functions will fail if:
  65 .sp
  66 .ne 2
  67 .mk
  68 .na
  69 \fBRange Error\fR
  70 .ad
  71 .RS 15n
  72 .rt  
  73 The result overflows.
  74 .sp
  75 If the integer expression (\fBmath_errhandling\fR & \fBMATH_ERREXCEPT\fR) is
  76 non-zero, the overflow floating-point exception is raised.
  77 .sp
  78 The \fBexp()\fR function sets \fBerrno\fR to \fBERANGE\fR if the result
  79 overflows.
  80 .RE
  81 
  82 .SH USAGE
  83 .sp
  84 .LP
  85 An application wanting to check for exceptions should call
  86 \fBfeclearexcept\fR(\fBFE_ALL_EXCEPT\fR) before calling these functions. On
  87 return, if \fBfetestexcept\fR(\fBFE_INVALID\fR | \fBFE_DIVBYZERO\fR |
  88 \fBFE_OVERFLOW\fR | \fBFE_UNDERFLOW\fR) is non-zero, an exception has been
  89 raised. An application should either examine the return value or check the
  90 floating point exception flags to detect exceptions.
  91 .sp
  92 .LP
  93 An application can also set \fBerrno\fR to 0 before calling \fBexp()\fR. On
  94 return, if \fBerrno\fR is non-zero, an error has occurred. The \fBexpf()\fR and
  95 \fBexpl()\fR functions do not set \fBerrno\fR.
  96 .SH ATTRIBUTES
  97 .sp
  98 .LP
  99 See \fBattributes\fR(5) for descriptions of the following attributes:
 100 .sp
 101 
 102 .sp
 103 .TS
 104 tab() box;
 105 cw(2.75i) |cw(2.75i) 
 106 lw(2.75i) |lw(2.75i) 
 107 .
 108 ATTRIBUTE TYPEATTRIBUTE VALUE
 109 _
 110 Interface StabilityStandard
 111 _
 112 MT-LevelMT-Safe
 113 .TE
 114 
 115 .SH SEE ALSO
 116 .sp
 117 .LP
 118 \fBfeclearexcept\fR(3M), \fBfetestexcept\fR(3M), \fBisnan\fR(3M),
 119 \fBlog\fR(3M), \fBmath.h\fR(3HEAD), \fBmatherr\fR(3M), \fBmp\fR(3MP),
 120 \fBattributes\fR(5), \fBstandards\fR(5)