IRIX Base Documentation 2001 May

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Text File | 1998-10-30 | 15.5 KB | 892 lines

MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) NNNNAAAAMMMMEEEE matherr - error-handling function SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS ####iiiinnnncccclllluuuuddddeeee <<<<mmmmaaaatttthhhh....hhhh>>>> iiiinnnntttt mmmmaaaatttthhhheeeerrrrrrrr ((((ssssttttrrrruuuucccctttt eeeexxxxcccceeeeppppttttiiiioooonnnn ****xxxx))));;;; DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN mmmmaaaatttthhhheeeerrrrrrrr is invoked by the following functions in libmx.a when errors are detected: acos acosf acosh asin asinf asinh atan atanf atan2 atan2f atanh cbrt cos cosf cosh coshf drem erf erfc exp expf expm1 expm1f fmod fmodf gamma hypot hypotf j0 j1 jn lgamma log logf log10 log10f log1p log1pf pow powf sin sinf sinh sinhf sqrt sqrtf tan tanf tanh tanhf y0 y1 yn Note that to use mmmmaaaatttthhhheeeerrrrrrrr, libmx.a needs to be linked with the program. Users may define their own routines for handling errors by including a function named mmmmaaaatttthhhheeeerrrrrrrr in their programs. mmmmaaaatttthhhheeeerrrrrrrr must be of the form described above. When an error occurs, a pointer to the exception structure _x will be passed to the user-supplied mmmmaaaatttthhhheeeerrrrrrrr function. This structure, which is defined in the _m_a_t_h._h header file, is as follows: struct exception { int type; char *name; double arg1, arg2, retval; }; The element _t_y_p_e is an integer describing the type of error that has occurred, from the following list of constants (defined in the header file math.h): DOMAIN argument domain error SING argument singularity OVERFLOW overflow range error UNDERFLOW underflow range error TLOSS total loss of significance PLOSS partial loss of significance The element _n_a_m_e points to a string containing the name of the function that incurred the error. The elements _a_r_g_1 and _a_r_g_2 are the arguments with which the function was invoked. _r_e_t_v_a_l is set to the default value that will be returned by the function unless the user's mmmmaaaatttthhhheeeerrrrrrrr sets it to a different value. NaN argument(s) to any of the above functions generates a call to matherr with a domain error. PPPPaaaaggggeeee 1111 MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) If the user's mmmmaaaatttthhhheeeerrrrrrrr function returns non-zero, no error message will be printed by the calling function, and _e_r_r_n_o will not be set. If mmmmaaaatttthhhheeeerrrrrrrr is not supplied by the user, the default error-handling procedures, described by the table below, will be invoked upon error. In every case, _e_r_r_n_o is set to EDOM or ERANGE and the program continues. PPPPaaaaggggeeee 2222 MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) _______________________________________________________________________________ Default Error Handling Procedures ______________________________________________________________________________ Types of Errors ______________________________________________________________________________ type DOMAIN SING OVERFLOW UNDERFLOW TLOSS PLOSS ______________________________________________________________________________ errno EDOM EDOM ERANGE ERANGE ERANGE ERANGE ______________________________________________________________________________ EXP, EXPF: - - M, H M, 0 - - ______________________________________________________________________________ EXPM1, EXPM1F: - - M, H M, 0 - - ______________________________________________________________________________ LOG, LOGF: LOG10, LOG10F: (arg < 0) M, N - - - - - (arg = 0) M, -H - - - - - ______________________________________________________________________________ LOG1P, LOG1PF: (arg < -1) M, N - - - - - (arg = -1) M, -H - - - - - ______________________________________________________________________________ POW, POWF: - - +_H 0 - - neg ** non-int M, 0 - - - - - 0 ** non-pos M, H - - - - - ______________________________________________________________________________ SQRT, SQRTF: M, N - - - - - ______________________________________________________________________________ DREM, FMOD, FMODF: (arg1 = +/-inf M, N - - - - - or arg2 = 0) ______________________________________________________________________________ GAMMA, LGAMMA: - M, H M, H - - - ______________________________________________________________________________ J0, J1, JN: - - - - M, 0 - ______________________________________________________________________________ Y0, Y1, YN: (arg = 0) - - M, -H - - - (arg < 0) M, N - - - - - (arg >= 2**49) - - - - M, 0 - ______________________________________________________________________________ SINH, SINHF: - - +_H - - - ______________________________________________________________________________ COSH, COSHF: - - H - - - ______________________________________________________________________________ HYPOT, HYPOTF: - - M, H - - - ______________________________________________________________________________ ASIN, ASINF: ACOS, ACOSF: M, N - - - - - ______________________________________________________________________________ ______________________________________________________________________________ |||||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||| ||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||||||||||||||||||||||||||||||||||||| PPPPaaaaggggeeee 3333 MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) SIN, COS, TAN: (arg >= 2**50) M, N - - - - - (arg = +/-inf) - - - - M, 0 - ______________________________________________________________________________ SINF, COSF, TANF: (arg >= 2**22) M, N - - - - - (arg = +/-inf) - - - - M, 0 - ______________________________________________________________________________ ATAN2, ATAN2F: M, 0 - - - - - ______________________________________________________________________________ ACOSH: M, N - - - - - ______________________________________________________________________________ ATANH: (|arg| > 1) M, N - - - - - ______________________________________________________________________________ ||||||||||||||| ||||||||||||||| ||||||||||||||| ||||||||||||||| ||||||||||||||| ||||||||||||||| ||||||||||||||| ||||||||||||||| ______________________________________________________________________________ Abbreviations M Message is printed H HUGE is returned -H -HUGE is returned +_H HUGE or -HUGE is returned. 0 0 is returned. X _a_r_g_1 is returned. N NaN is returned. ______________________________________________________________________________ ||||||||| ||||||||| PPPPaaaaggggeeee 4444 MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) EEEEXXXXAAAAMMMMPPPPLLLLEEEE /* ** Example showing the use of libmx.a's matherr() to handle math errors. ** ** % cc -xansi my_matherr.c -lmx ** % a.out ** overflow range error in logf ** logf(0.0) is -inf. ** ** expf failed: Argument out of domain ** Abort (core dumped) */ #include <stdio.h> #include <math.h> #include <stdlib.h> #include <string.h> #include <errno.h> main() { float ff; ff = logf(0.0f); /* matherr() leaves error reporting to libmx.a */ printf("logf(0.0f) is %f.\n\n",ff); fflush(stdout); ff = 0.0f; ff = 0.0f/ff; ff = expf(ff); /* matherr() customized to force a core dump */ } int matherr( register struct exception *x ) { char *sterr; switch (x->type) { case DOMAIN: /* if it's a NaN, abort */ if ( isnan(x->arg1) ) { sterr = strerror(EDOM); fprintf(stderr, "%s failed: %s\n", x->name, sterr); abort(); } else if ( !strcmp(x->name, "sin") ) { x->retval = 0.0; /* return 0.0 */ fprintf(stderr, "domain error in sin\n"); PPPPaaaaggggeeee 5555 MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) MMMMAAAATTTTHHHHEEEERRRRRRRR((((3333MMMM)))) return (1); /* suppress libmx.a error message and setting of errno */ } else return (0); /* libmx.a prints error message and sets errno */ break; default: return (0); /* libmx.a prints error message and sets errno */ } } NNNNOOOOTTTTEEEESSSS Errors detected by functions in libm.a can be detected by examining the return value and/or the global variable _e_r_r_n_o. libmx.a is provided as an alternative error handling scheme for users who want to identify specific kinds of errors determined by libm functions without extensive modification of their source code. No extra overhead is incurred by programs using libmx.a if no error conditions are encountered in the libmx routines. PPPPaaaaggggeeee 6666