# tgammaf(3m) [opensolaris man page]

tgamma(3M) Mathematical Library Functions tgamma(3M)NAME

tgamma, tgammaf, tgammal - compute gamma functionSYNOPSIS

c99 [ flag... ] file...[ library... ] #include <math.h> double tgamma(double x); float tgammaf(float x); long double tgammal(long double x);-lmDESCRIPTION

These functions compute the gamma() function of x.RETURN VALUES

Upon successful completion, these functions return gamma(x). If x is a negative integer, a domain error occurs and a NaN is returned. If the correct value would cause overflow, a range error occurs and tgamma(), tgammaf(), and tgammal() return the value of the macro +-HUGE_VAL, +-HUGE_VALF, or +-HUGE_VALL, respectively. If x is NaN, a NaN is returned. If x is +-Inf, x is returned. If x is +-0, a pole error occurs and tgamma(), tgammaf(), and tgammal() return +-HUGE_VAL, +-HUGE_VALF, and +-HUGE_VALL, respectively. If x is +Inf, a domain error occurs and a NaN is returned.ERRORS

These functions will fail if: Domain Error The value of x is a negative integer or x isIf the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception is raised. Pole Error The value of x is zero. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the divide-by-zero floating-point exception is raised. Range Error The value overflows. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception is raised.-Inf.USAGE

An application wanting to check for exceptions should call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an exception has been raised. An application should either examine the return value or check the floating point exception flags to detect exceptions.ATTRIBUTES

See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+SEE ALSO

feclearexcept(3M), fetestexcept(3M), lgamma(3M), math.h(3HEAD), attributes(5), standards(5)SunOS 5.1112 Jul 2006 tgamma(3M)

## Check Out this Related Man Page

TGAMMA(3P) POSIX Programmer's Manual TGAMMA(3P)PROLOG

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAME

tgamma, tgammaf, tgammal - compute gamma() functionSYNOPSIS

#include <math.h> double tgamma(double x); float tgammaf(float x); long double tgammal(long double x);DESCRIPTION

These functions shall compute the gamma() function of x. An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these functions. On return, if errno is non-zero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error has occurred.RETURN VALUE

Upon successful completion, these functions shall return Gamma( x). If x is a negative integer, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned. If the correct value would cause overflow, a range error shall occur and tgamma(), tgammaf(), and tgammal() shall return +-HUGE_VAL, +-HUGE_VALF, or +-HUGE_VALL, respectively, with the same sign as the correct value of the function. If x is NaN, a NaN shall be returned. If x is +Inf, x shall be returned. If x is +-0, a pole error shall occur, and tgamma(), tgammaf(), and tgammal() shall return +-HUGE_VAL, +-HUGE_VALF, and +-HUGE_VALL, respectively. If x is, a domain error shall occur, and either a NaN (if supported), or an implementation-defined value shall be returned.-InfERRORS

These functions shall fail if: Domain Error The value of x is a negative integer, or x isIf the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the invalid floating-point exception shall be raised. Pole Error The value of x is zero. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the divide-by-zero floating-point exception shall be raised. Range Error The value overflows. If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be set to [ERANGE]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is non-zero, then the overflow floating-point exception shall be raised. The following sections are informative.-Inf.EXAMPLES

None.APPLICATION USAGE

For IEEE Std 754-1985 double, overflow happens when 0 < x < 1/DBL_MAX, and 171.7 < x. On error, the expressions (math_errhandling & MATH_ERRNO) and (math_errhandling & MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.RATIONALE

This function is named tgamma() in order to avoid conflicts with the historical gamma() and lgamma() functions.FUTURE DIRECTIONS

It is possible that the error response for a negative integer argument may be changed to a pole error and a return value of +-Inf.SEE ALSO

feclearexcept(), fetestexcept(), lgamma(), the Base Definitions volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathematical Functions, <math.h>COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogyPortable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .--IEEE

/The Open Group 2003 TGAMMA(3P)