.\"	$NetBSD: strsuftoll.3,v 1.11 2010/12/14 13:00:34 jruoho Exp $
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.\" by Luke Mewburn.
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.Dd December 14, 2010
.Dt STRSUFTOLL 3
.Os
.Sh NAME
.Nm strsuftoll ,
.Nm strsuftollx
.Nd "convert a string to a long long, with suffix parsing"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft long long
.Fn strsuftoll "const char *desc" "const char *val" "long long min" "long long max"
.Ft long long
.Fn strsuftollx "const char *desc" "const char *val" "long long min" "long long max" "char *errbuf" "size_t errbuflen"
.Sh DESCRIPTION
The functions
.Fn strsuftoll
and
.Fn strsuftollx
convert
.Fa val
into a number of type
.Vt long long ,
checking that the result is not smaller than
.Fa min
or larger than
.Fa max .
Two or more decimal numbers may be separated by an
.Dq x
to indicate a product.
.Pp
Each decimal number may have one of the following optional suffixes:
.Pp
.Bl -tag -width 3n -offset indent -compact
.It Em b
Block; multiply by 512
.It Em k
Kibi; multiply by 1024 (1 KiB)
.It Em m
Mebi; multiply by 1048576 (1 MiB)
.It Em g
Gibi; multiply by 1073741824 (1 GiB)
.It Em t
Tebi; multiply by 1099511627776 (1 TiB)
.It Em w
Word; multiply by the number of bytes in an integer
.El
.Pp
In the case of an error (range overflow or an invalid number),
.Fn strsuftollx
places an error message into
.Fa errbuf
(which is
.Fa errbuflen
bytes long) and returns 0,
and
.Fn strsuftoll
displays that error and terminates the process.
The parameter
.Fa desc
is used to construct
.Fa errbuf .
.Pp
Neither
.Fa desc
nor
.Fa val
may be
.Dv NULL .
.Sh RETURN VALUES
The functions
.Fn strsuftoll
and
.Fn strsuftollx
return either the result of the conversion,
unless the value overflows or is not a number;
in the latter case,
.Fn strsuftoll
displays an error message and terminates the process with exit code
.Dv EXIT_FAILURE ,
and
.Fn strsuftollx
returns with 0 and
.Fa errbuf
contains a non-empty error message.
.Sh ERRORS
.Bl -tag -width Er
.It Bq Er ERANGE
The given string was out of range; the value converted has been clamped.
.El
.Sh SEE ALSO
.Xr errx 3 ,
.Xr strtoll 3 ,
.Xr orders 7
.Sh BUGS
At least few limitations should be mentioned:
.Bl -bullet
.It
Both functions ignore the current locale.
.It
Neither
.Fn strsuftoll
nor
.Fn strsuftollx
fail gracefully in case of invalid,
.Dv NULL ,
pointers.
.It
Arguably the return type should be
.Vt intmax_t
instead of
.Vt long long .
.It
The
.Fn strsuftollx
function is prone to buffer overflows if used incorrectly.
Arguably only
.Fn strsuftoll
should be exposed to a caller.
.El