.TH GAMMA 3M .CT 2 math .SH NAME gamma \(mi log gamma function .SH SYNOPSIS .nf .B #include <math.h> .PP .B double gamma(x) .B double x; .PP .B extern int signgam; .fi .SH DESCRIPTION .I Gamma returns ln |\(*G(\|\fIx\fP\|)|. The sign of \(*G(\|\fIx\fP\|) is returned in the external integer .IR signgam . .SH EXAMPLES Computation of the gamma function: .PP .nf .ta 8n +8n .ft L errno = 0; y = gamma(x); if(errno || (y > 88.0)) error(); y = signgam*exp(y); .fi .ft P .SH DIAGNOSTICS A large value .RL ( HUGE ) is returned for negative integer arguments and .I errno is set to .BR EDOM . .SH BUGS There should be a positive indication of error. .br The name should indicate the answer is a logarithm, perhaps .IR lgamma .