ecvt.3

unix v7是最后一个广泛发布的研究型UNIX版本

.TH ECVT 3 
.SH NAME
ecvt, fcvt, gcvt \- output conversion
.SH SYNOPSIS
.B char *ecvt(value, ndigit, decpt, sign)
.br
.B double value;
.br
.B int ndigit, *decpt, *sign;
.PP
.B char *fcvt(value, ndigit, decpt, sign)
.br
.B double value;
.br
.B int ndigit, *decpt, *sign;
.PP
.B char *gcvt(value, ndigit, buf)
.br
.B double value;
.br
.B char *buf;
.SH DESCRIPTION
.I Ecvt
converts the 
.I value
to a null-terminated string of
.I ndigit
ASCII digits
and returns a pointer thereto.
The position of the decimal point relative to the
beginning of the string is stored indirectly
through
.IR decpt ""
(negative means to the left of the
returned digits).
If the sign of the result is negative,
the word pointed to by
.IR sign ""
is non-zero, otherwise
it is zero.
The low-order digit is rounded.
.PP
.IR Fcvt " is identical to " "ecvt\fR, except that the correct digit"
has been rounded for Fortran F-format output of the number
of digits specified by
.IR \(*_ndigits .
.PP
.I Gcvt
converts the
.I value
to a null-terminated ASCII string in
.I buf
and returns a pointer to 
.I buf.
It attempts to produce
.I ndigit
significant digits in Fortran F format if
possible, otherwise E format, ready for
printing.
Trailing zeros may be suppressed.
.SH "SEE ALSO"
printf(3)
.SH BUGS
The return values point to static data
whose content is overwritten by each call.