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-rw-r--r--src/corelib/kernel/qmath.qdoc19
1 files changed, 18 insertions, 1 deletions
diff --git a/src/corelib/kernel/qmath.qdoc b/src/corelib/kernel/qmath.qdoc
index 3a692d5935..a2e24e925b 100644
--- a/src/corelib/kernel/qmath.qdoc
+++ b/src/corelib/kernel/qmath.qdoc
@@ -35,7 +35,24 @@
These functions are partly convenience definitions for basic math operations
not available in the C or Standard Template Libraries.
- \pagekeywords math trigonometry qmath floor ceiling absolute sine cosine tangent inverse tan exponent power natural logarithm
+ The header also ensures some constants specified in POSIX, but not present
+ in C++ standards (so absent from <math.h> on some platforms), are defined:
+
+ \value M_E The base of the natural logarithms, e = exp(1)
+ \value M_LOG2E The base-two logarithm of e
+ \value M_LOG10E The base-ten logarithm of e
+ \value M_LN2 The natural logarithm of two
+ \value M_LN10 The natural logarithm of ten
+ \value M_PI The ratio of a circle's circumference to diameter, \unicode{0x3C0}
+ \value M_PI_2 Half M_PI, \unicode{0x3C0} / 2
+ \value M_PI_4 Quarter M_PI, \unicode{0x3C0} / 4
+ \value M_1_PI The inverse of M_PI, 1 / \unicode{0x3C0}
+ \value M_2_PI Twice the inverse of M_PI, 2 / \unicode{0x3C0}
+ \value M_2_SQRTPI Two divided by the square root of pi, 2 / \unicode{0x221A}\unicode{0x3C0}
+ \value M_SQRT2 The square root of two, \unicode{0x221A}2
+ \value M_SQRT1_2 The square roof of half, 1 / \unicode{0x221A}2
+
+ \pagekeywords math trigonometry qmath floor ceiling absolute sine cosine tangent inverse tan exponent power natural logarithm pi
*/
/*!