Improve detection of errors from math functions

Checking errno is not always sufficient; check for floating-point
exceptions, too.

Author: Tim van der Molen

lib.c

@@ -828,21 +828,6 @@ void bclass(int c)
 	}
 }
 
-double errcheck(double x, const char *s)
-{
-
-	if (errno == EDOM) {
-		errno = 0;
-		WARNING("%s argument out of domain", s);
-		x = 1;
-	} else if (errno == ERANGE) {
-		errno = 0;
-		WARNING("%s result out of range", s);
-		x = 1;
-	}
-	return x;
-}
-
 int isclvar(const char *s)	/* is s of form var=something ? */
 {
 	const char *os = s;

makefile

@@ -40,7 +40,7 @@ CC = $(HOSTCC)  # change this is cross-compiling.
 # YACC = yacc -d -b awkgram
 YACC = bison -d
 
-OFILES = b.o main.o parse.o proctab.o tran.o lib.o run.o lex.o
+OFILES = b.o main.o parse.o proctab.o tran.o lib.o run.o lex.o math.o
 
 SOURCE = awk.h awkgram.tab.c awkgram.tab.h proto.h awkgram.y lex.c b.c main.c \
 	maketab.c parse.c lib.c run.c tran.c proctab.c

math.c

@@ -0,0 +1,94 @@
+/****************************************************************
+Copyright (C) Lucent Technologies 1997
+All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby
+granted, provided that the above copyright notice appear in all
+copies and that both that the copyright notice and this
+permission notice and warranty disclaimer appear in supporting
+documentation, and that the name Lucent Technologies or any of
+its entities not be used in advertising or publicity pertaining
+to distribution of the software without specific, written prior
+permission.
+
+LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
+SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
+IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.
+****************************************************************/
+
+#pragma STDC FENV_ACCESS ON
+
+#include <errno.h>
+#include <fenv.h>
+#include <math.h>
+#include <stdio.h>
+
+#include "awk.h"
+
+#ifndef FE_DIVBYZERO
+#define FE_DIVBYZERO 0
+#endif
+
+#ifndef FE_INVALID
+#define FE_INVALID 0
+#endif
+
+#ifndef FE_OVERFLOW
+#define FE_OVERFLOW 0
+#endif
+
+#ifndef FE_UNDERFLOW
+#define FE_UNDERFLOW 0
+#endif
+
+#define errclear()							\
+	do {								\
+		errno = 0;						\
+		feclearexcept(FE_ALL_EXCEPT);				\
+	} while (0)
+
+static double errcheck(double x, const char *s)
+{
+	if (errno == EDOM || fetestexcept(FE_INVALID)) {
+		errno = 0;
+		WARNING("%s argument out of domain", s);
+		x = 1;
+	} else if (errno == ERANGE || fetestexcept(FE_DIVBYZERO | FE_OVERFLOW |
+	    FE_UNDERFLOW)) {
+		errno = 0;
+		WARNING("%s result out of range", s);
+		x = 1;
+	}
+
+	return x;
+}
+
+double exp_errcheck(double x)
+{
+	errclear();
+	return errcheck(exp(x), "exp");
+}
+
+double log_errcheck(double x)
+{
+	errclear();
+	return errcheck(log(x), "log");
+}
+
+double pow_errcheck(double x, double y)
+{
+	errclear();
+	return errcheck(pow(x, y), "pow");
+}
+
+double sqrt_errcheck(double x)
+{
+	errclear();
+	return errcheck(sqrt(x), "sqrt");
+}

proto.h

@@ -140,7 +140,6 @@ extern	void	WARNING(const char *, ...)
 extern	void	error(void);
 extern	void	eprint(void);
 extern	void	bclass(int);
-extern	double	errcheck(double, const char *);
 extern	int	isclvar(const char *);
 extern	bool	is_valid_number(const char *s, bool trailing_stuff_ok,
 				bool *no_trailing, double *result);
@@ -198,3 +197,8 @@ extern	FILE	*popen(const char *, const char *);
 extern	int	pclose(FILE *);
 
 extern  const char	*flags2str(int flags);
+
+extern	double	exp_errcheck(double);
+extern	double	log_errcheck(double);
+extern	double	pow_errcheck(double, double);
+extern	double	sqrt_errcheck(double);

run.c

@@ -25,7 +25,6 @@ THIS SOFTWARE.
 #define DEBUG
 #include <stdio.h>
 #include <ctype.h>
-#include <errno.h>
 #include <wctype.h>
 #include <fcntl.h>
 #include <setjmp.h>
@@ -1486,10 +1485,8 @@ Cell *arith(Node **a, int n)	/* a[0] + a[1], etc.  also -a[0] */
 	case POWER:
 		if (j >= 0 && modf(j, &v) == 0.0)	/* pos integer exponent */
 			i = ipow(i, (int) j);
-               else {
-			errno = 0;
-			i = errcheck(pow(i, j), "pow");
-               }
+               else
+			i = pow_errcheck(i, j);
 		break;
 	default:	/* can't happen */
 		FATAL("illegal arithmetic operator %d", n);
@@ -1583,10 +1580,8 @@ Cell *assign(Node **a, int n)	/* a[0] = a[1], a[0] += a[1], etc. */
 	case POWEQ:
 		if (yf >= 0 && modf(yf, &v) == 0.0)	/* pos integer exponent */
 			xf = ipow(xf, (int) yf);
-               else {
-			errno = 0;
-			xf = errcheck(pow(xf, yf), "pow");
-               }
+               else
+			xf = pow_errcheck(xf, yf);
 		break;
 	default:
 		FATAL("illegal assignment operator %d", n);
@@ -2081,18 +2076,15 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 			u = u8_strlen(getsval(x));
 		break;
 	case FLOG:
-		errno = 0;
-		u = errcheck(log(getfval(x)), "log");
+		u = log_errcheck(getfval(x));
 		break;
 	case FINT:
 		modf(getfval(x), &u); break;
 	case FEXP:
-		errno = 0;
-		u = errcheck(exp(getfval(x)), "exp");
+		u = exp_errcheck(getfval(x));
 		break;
 	case FSQRT:
-		errno = 0;
-		u = errcheck(sqrt(getfval(x)), "sqrt");
+		u = sqrt_errcheck(getfval(x));
 		break;
 	case FSIN:
 		u = sin(getfval(x)); break;