ecvt.3c (2010 09)

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ecvt(3C) ecvt(3C)
NAME
ecvt( ), fcvt( ), gcvt( ) - convert floating-point number to string
SYNOPSIS
#include <stdlib.h>
char *ecvt(double value, int ndigit, int *__restrict decpt, int *__res-
trict sign);
char *fcvt(double value, int ndigit, int *__restrict decpt, int *__res-
trict sign);
char *gcvt(double value, int ndigit, char *buf);
Obsolescent Interfaces
int ecvt_r(
double value,
int ndigit,
int *decpt,
int *sign,
char *buffer,
int buflen);
int fcvt_r(
double value,
int ndigit,
int *decpt,
int *sign,
char *buffer,
int buflen);
DESCRIPTION
ecvt() Converts value to a null-terminated string of ndigit digits and returns a pointer to the
string. The high-order digit is non-zero, unless the value is zero. The low-order digit is
rounded. The position of the radix character relative to the beginning of the string is stored
indirectly through decpt (negative means to the left of the returned digits). The radix char-
acter is not included in the returned string. If the sign of the result is negative, the word
pointed to by sign is non-zero, otherwise it is zero.
One of three non-digit characters strings could be returned if the converted value is out of
range. A
-- or ++ is returned if the value is larger than the exponent can contain, and is
negative, or positive, respectively. The third string is returned if the number is illegal, a
zero divide for example. The result value is Not A Number (NAN) and would return a
?
character.
fcvt() Identical to ecvt(), except that the correct digit has been rounded for printf %f (FORTRAN
F-format) output of the number of digits specified by ndigit .
gcvt() Converts the value to a null-terminated string in the array pointed to by buf and returns
buf. It produces ndigit significant digits in FORTRAN F-format if possible, or E-format other-
wise. A minus sign, if required, and a radix character is included in the returned string.
Trailing zeros are suppressed. The radix character is determined by the currently loaded
NLS environment (see setlocale (3C)). If setlocale() has not been called successfully,
the default NLS environment, "C", is used (see lang(5)). The default environment specifies a
period (.) as the radix character.
Obsolescent Interfaces
ecvt_r() and fcvt_r() convert floating-point number to string.
EXTERNAL INFLUENCES
Locale
The
LC_NUMERIC category determines the value of the radix character within the current NLS environ-
ment.
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