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HP-UX Reference > Aatan(3M)HP-UX 11i Version 2: December 2007 Update |
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NAMEatan(), atanf(), atanl(), atanw(), atanq() — arctangent functions DESCRIPTIONatan() returns the arctangent of x, in the range -π/2 to π/2. atanf() is a float version of atan(); it takes a float argument and returns a float result. USAGETo use these functions compile either with the default -Ae option or with the -Aa and the -D_HPUX_SOURCE options. To use (for Integrity servers) atanw() or atanq(), compile also with -fpwidetypes. To use any of these functions, make sure your program includes <math.h>, and link in the math library by specifying -lm on the compiler or linker command line. For more information, see the HP-UX floating-point guide for HP Integrity servers at the following site: http://www.hp.com/go/fp. PA-RISC OnlyMillicode versions of the atan() and atanf() functions are available. Millicode versions of math library functions are usually faster than their counterparts in the standard library. To use these versions, compile your program with the +Olibcalls or the +Oaggressive optimization option. For special cases, the millicode versions return the same values as their standard library counterparts (see the RETURN VALUE section). |
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