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46 .TH MATH.H 3HEAD "Aug 11, 2004"
47 .SH NAME
48 math.h, math \- mathematical declarations
49 .SH SYNOPSIS
50 .LP
51 .nf
52 \fB#include <math.h>\fR
53 .fi
55 .SH DESCRIPTION
56 .sp
57 .LP
58 The <\fBmath.h\fR> header includes definitions for the following types:
59 .sp
60 .ne 2
61 .na
62 \fB\fBfloat_t\fR\fR
63 .ad
64 .RS 12n
65 A real-floating type at least as wide as \fBfloat\fR.
66 .RE
68 .sp
69 .ne 2
70 .na
71 \fB\fBdouble_t\fR\fR
72 .ad
73 .RS 12n
74 A real-floating type at least as wide as \fBdouble\fR, and at least as wide as
75 \fBfloat_t\fR.
76 .RE
78 .sp
79 .LP
80 If \fBFLT_EVAL_METHOD\fR equals 0, \fBfloat_t\fR and \fBdouble_t\fR are
81 \fBfloat\fR and \fBdouble\fR, respectively. If \fBFLT_EVAL_METHOD\fR equals 1,
82 they are both \fBdouble\fR. If \fBFLT_EVAL_METHOD\fR equals 2, they are both be
83 \fBlong double\fR. Other values of \fBFLT_EVAL_METHOD\fR are
84 implementation-defined.
85 .sp
86 .LP
87 The <\fBmath.h\fR> header provides the following constants. The values are of
88 type \fBdouble\fR and are accurate within the precision of the \fBdouble\fR
89 type.
90 .sp
91 .ne 2
92 .na
93 \fB\fBM_E\fR\fR
94 .ad
95 .RS 14n
96 The base of natural logarithms (\fIe\fR).
97 .RE
99 .sp
100 .ne 2
101 .na
102 \fB\fBM_LOG2E\fR\fR
103 .ad
104 .RS 14n
105 The base-2 logarithm of \fIe\fR.
106 .RE
108 .sp
109 .ne 2
110 .na
111 \fB\fBM_LOG10E\fR\fR
112 .ad
113 .RS 14n
114 The base-10 logarithm of \fIe\fR.
115 .RE
117 .sp
118 .ne 2
119 .na
120 \fB\fBM_LN2\fR\fR
121 .ad
122 .RS 14n
123 The natural logarithm of 2.
124 .RE
126 .sp
127 .ne 2
128 .na
129 \fB\fBM_LN10\fR\fR
130 .ad
131 .RS 14n
132 The natural logarithm of 10.
133 .RE
135 .sp
136 .ne 2
137 .na
138 \fB\fBM_PI\fR\fR
139 .ad
140 .RS 14n
141 \c
142 .if n pi\c
143 .if t \(*p
144 \c
145 , the ratio of the circumference of a circle to its diameter.
146 .RE
148 .sp
149 .ne 2
150 .na
151 \fB\fBM_PI_2\fR\fR
152 .ad
153 .RS 14n
154 \c
155 .if n pi\c
156 .if t \(*p
157 \c
158 /2.
159 .RE
161 .sp
162 .ne 2
163 .na
164 \fB\fBM_PI_4\fR\fR
165 .ad
166 .RS 14n
167 \c
168 .if n pi\c
169 .if t \(*p
170 \c
171 /4.
172 .RE
174 .sp
175 .ne 2
176 .na
177 \fB\fBM_1_PI\fR\fR
178 .ad
179 .RS 14n
180 1/\c
181 .if n pi\c
182 .if t \(*p
183 \c
184 .
185 .RE
187 .sp
188 .ne 2
189 .na
190 \fB\fBM_2_PI\fR\fR
191 .ad
192 .RS 14n
193 2/\c
194 .if n pi\c
195 .if t \(*p
196 \c
197 .
198 .RE
200 .sp
201 .ne 2
202 .na
203 \fB\fBM_2_SQRTPI\fR\fR
204 .ad
205 .RS 14n
206 2 over the square root of \c
207 .if n pi\c
208 .if t \(*p
209 \c
210 .
211 .RE
213 .sp
214 .ne 2
215 .na
216 \fB\fBM_SQRT2\fR\fR
217 .ad
218 .RS 14n
219 The positive square root of 2.
220 .RE
222 .sp
223 .ne 2
224 .na
225 \fB\fBM_SQRT1_2\fR\fR
226 .ad
227 .RS 14n
228 The positive square root of 1/2.
229 .RE
231 .sp
232 .LP
233 The <\fBmath.h\fR> header defines the following symbolic constants:
234 .sp
235 .ne 2
236 .na
237 \fB\fBMAXFLOAT\fR\fR
238 .ad
239 .RS 13n
240 The maximum value of a non-infinite single-precision floating point number.
241 .RE
243 .sp
244 .ne 2
245 .na
246 \fB\fBHUGE_VAL\fR\fR
247 .ad
248 .RS 13n
249 A positive \fBdouble\fR expression, not necessarily representable as a float.
250 Used as an error value returned by the mathematics library. \fBHUGE_VAL\fR
251 evaluates to +infinity on systems supporting IEEE Std 754-1985.
252 .RE
254 .sp
255 .ne 2
256 .na
257 \fB\fBHUGE_VALF\fR\fR
258 .ad
259 .RS 13n
260 A positive \fBfloat\fR constant expression. Used as an error value returned by
261 the mathematics library. \fBHUGE_VALF\fR evaluates to +infinity on systems
262 supporting IEEE Std 754-1985.
263 .RE
265 .sp
266 .ne 2
267 .na
268 \fB\fBHUGE_VALL\fR\fR
269 .ad
270 .RS 13n
271 A positive \fBlong double\fR constant expression. Used as an error value
272 returned by the mathematics library. \fBHUGE_VALL\fR evaluates to +infinity on
273 systems supporting IEEE Std 754-1985.
274 .RE
276 .sp
277 .ne 2
278 .na
279 \fB\fBINFINITY\fR\fR
280 .ad
281 .RS 13n
282 A constant expression of type \fBfloat\fR representing positive or unsigned
283 infinity, if available; else a positive constant of type \fBfloat\fR that
284 overflows at translation time.
285 .RE
287 .sp
288 .ne 2
289 .na
290 \fB\fBNAN\fR\fR
291 .ad
292 .RS 13n
293 A constant expression of type float representing a quiet NaN. This symbolic
294 constant is only defined if the implementation supports quiet NaNs for the
295 \fBfloat\fR type.
296 .RE
298 .sp
299 .LP
300 The following macros are defined for number classification. They represent the
301 mutually-exclusive kinds of floating-point values. They expand to integer
302 constant expressions with distinct values
303 .sp
304 .in +2
305 .nf
306 FP_INFINITE
307 FP_NAN
308 FP_NORMAL
309 FP_SUBNORMAL
310 FP_ZERO
311 .fi
312 .in -2
314 .sp
315 .LP
316 The following optional macros indicate whether the \fBfma()\fR family of
317 functions are fast compared with direct code:
318 .sp
319 .in +2
320 .nf
321 FP_FAST_FMA
322 FP_FAST_FMAF
323 FP_FAST_FMAL
324 .fi
325 .in -2
327 .sp
328 .LP
329 The \fBFP_FAST_FMA\fR macro is defined to indicate that the \fBfma()\fR
330 function generally executes about as fast as, or faster than, a multiply and an
331 add of \fBdouble\fR operands. The other macros have the equivalent meaning for
332 the \fBfloat\fR and \fBlong double\fR versions.
333 .sp
334 .LP
335 The following macros expand to integer constant expressions whose values are
336 returned by \fBilogb\fR(\fIx\fR) if \fIx\fR is zero or NaN, respectively. The
337 value of \fBFP_ILOGB0\fR is either {\fBINT_MIN\fR} or -{\fBINT_MAX\fR}. The
338 value of \fBFP_ILOGBNAN\fR is either {\fBINT_MAX\fR} or {\fBINT_MIN\fR}.
339 .sp
340 .in +2
341 .nf
342 FP_ILOGB0
343 FP_ILOGBNAN
344 .fi
345 .in -2
347 .sp
348 .LP
349 The following macros expand to the integer constants 1 and 2, respectively:
350 .sp
351 .in +2
352 .nf
353 MATH_ERRNO
354 MATH_ERREXCEPT
355 .fi
356 .in -2
358 .sp
359 .LP
360 The following macro expands to an expression that has type \fBint\fR and the
361 value \fBMATH_ERREXCEPT\fR:
362 .sp
363 .in +2
364 .nf
365 math_errhandling
366 .fi
367 .in -2
369 .sp
370 .LP
371 The value of the macro \fBmath_errhandling\fR is constant for the duration of
372 the program. If a macro definition is suppressed or a program defines an
373 identifier with the name \fBmath_errhandling\fR, the behavior is undefined.
374 .sp
375 .LP
376 The <\fBmath.h\fR> header defines he following external variable:
377 .sp
378 .in +2
379 .nf
380 extern int signgam;
381 .fi
382 .in -2
384 .sp
385 .LP
386 The <\fBmath.h\fR> header defines the structure and constants used by the
387 \fBmatherr\fR(3M) error-handling mechanisms.
388 .SH ATTRIBUTES
389 .sp
390 .LP
391 See \fBattributes\fR(5) for descriptions of the following attributes:
392 .sp
394 .sp
395 .TS
396 box;
397 c | c
398 l | l .
399 ATTRIBUTE TYPE ATTRIBUTE VALUE
400 _
401 Interface Stability Standard
402 .TE
404 .SH SEE ALSO
405 .sp
406 .LP
407 \fBIntro\fR(3), \fBfenv.h\fR(3HEAD), \fBlibm\fR(3LIB), \fBlimits.h\fR(3HEAD),
408 \fBmatherr\fR(3M), \fBattributes\fR(5), \fBstandards\fR(5)