CLOG(3) BSD Library Functions Manual CLOG(3) NAME clog -- complex logarithm function SYNOPSIS #include <complex.h> double complex clog(double complex z); long double complex clogl(long double complex z); float complex clogf(float complex z); DESCRIPTION clog(z) returns the complex logarithm of z. clog(conj(z)) = conj(clog(z)), for all complex floating-point numbers z. SPECIAL VALUES The conjugate symmetry of clog() is used to abbreviate the specification of special values. clog(-0 + 0i) returns -inf + Pi i and raises the divide-by-zero flag. clog(0 + 0i) returns -inf + 0i and raises the divide-by-zero flag. clog(x + inf i) returns inf + Pi/2 i, for finite x. clog(x + NaN i) returns NaN + NaN i. clog(-inf + yi) returns inf + Pi i, for finite positive y. clog(inf + yi) returns inf + 0i, for finite positive y. clog(-inf + inf i) returns inf + 3Pi/4 i. clog(inf + inf i) returns inf + Pi/4 i. clog(+-inf + NaN i) returns inf + NaN i. clog(NaN + yi) returns NaN + NaN i, for finite y. clog(NaN + inf i) returns inf + NaN i. clog(NaN + NaN i) returns NaN + NaN i. NOTES SEE ALSO cexp(3) log(3) complex(3) STANDARDS The clog() function conforms to ISO/IEC 9899:2011. 4th Berkeley Distribution December 11, 2006 4th Berkeley Distribution