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clog(3M)

HP Integrity Server Only
HP-UX 11i Version 3: February 2007
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NAME

clog(), clogf(), clogl(), clogw(), clogq() — complex natural (base-e) logarithm functions

SYNOPSIS

#include <complex.h>

double complex clog(double complex z);

float complex clogf(float complex z);

long double complex clogl(long double complex z);

extended complex clogw(extended complex z);

quad complex clogq(quad complex z);

DESCRIPTION

These functions are available only for Integrity servers.

clog() returns the complex natural logarithm of z in the range of a strip mathematically unbounded along the real axis and in the interval [-iPi,+iPi] along the imaginary axis. There is a branch cut along the negative real axis.

clogf() is a float complex version of clog(); it takes a float complex argument and returns a float complex result.

clogl() is a long double complex version of clog(); it takes a long double complex argument and returns a long double complex result.

clogw() is an extended complex version of clog(); it takes an extended complex argument and returns an extended complex result.

clogq() is equivalent to clogl() on HP-UX systems.

USAGE

To use these functions, compile with the default -Ae option. To use clogw() or clogq(), compile with the -fpwidetypes option. Make sure your program includes <complex.h>. Link in the math library by specifying -lm on the compiler or linker command line.

RETURN VALUE

clog(conj(z)) = conj(clog(z)).

clog(-0+i0) returns -Inf+iPi and raises the divide-by-zero floating-point exception.

clog(+0+i0) returns -Inf+i0 and raises the divide-by-zero floating-point exception.

clog(x+iInf) returns +Inf+iPi/2, for finite x.

clog(x+iNaN) returns NaN+iNaN and optionally raises the invalid floating-point exception, for finite x.

clog(-Inf+iy) returns +Inf+iPi, for finite positive-signed y.

clog(+Inf+iy) returns +Inf+i0, for finite positive-signed y.

clog(-Inf+iInf) returns +Inf+i3Pi/4.

clog(+Inf+iInf) returns +Inf+ipi/4.

clog(±Inf+iNaN) returns +Inf+iNaN.

clog(NaN+iy) returns NaN+iNaN and optionally raises the invalid floating-point exception, for finite y.

clog(NaN+iInf) returns +Inf+iNaN.

clog(NaN+iNaN) returns NaN+iNaN.

ERRORS

No errors are defined.

STANDARDS CONFORMANCE

clog(), clogf(), clogl() : ISO/IEC C99 (including Annex G, ``IEC 60559-compatible complex arithmetic'')

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