Sprintf (Format Output String)

The Sprintf function is used to write a formatted output string to a destination variable.

Syntax

Length = Sprintf ( Dest, Format, Argument1..Argument10 )

The following program uses SprintF to format a string and sent it out the RS232 port.The two measurement instructions may need to be modified for other datalogger types.

The output string from this program can be seen by connecting a cable to the datalogger's RS232 port and using a terminal emulator (such as in Device Configuration Utility).

Public RefTemp, TCTemp
Public OutputString As String * 50

BeginProg
  'Open Serial port for communication
  SerialOpen (COMRS232,115200,0,0,50)

  Scan (5,Sec,3,0)
    PanelTemp (RefTemp,15000)
    TCDiff (TCTemp,1,mv200C,U1,TypeT,RefTemp,True,0,15000,1.0,0)
    
    'Generate string using SprintF
    '%f is used to format variable TCTemp
    '%c (formatting a character code of 10) outputs a line feed
    SprintF ( OutputString, "The current air temperature is %3.2f %c", TCTemp,10)

      SerialOut (COMRS232,OutputString,"",0,0)

    NextScan
EndProg

Remarks

The Sprintf function returns the length of the string written to the destination variable (Dest). Up to 10 arguments can be passed into the Format string, with format specifiers corresponding one-to-one with the arguments. The function requires an argument for each format specifier. Any arguments not paired with a format specifier are discarded.

Parameters

Dest (Destination)

Variable in which to store the formatted output string. Dest should be sized large enough to accommodate all of the characters written to the resulting string. No error is returned if Dest is sized too small.

Type: String variable

Format

A string used to define the format to be used for the arguments. Up to 10 format specifiers (with corresponding arguments) can be used in a format string. The format specifiers are:

Specifier Description
d or i  Signed decimal integer
u Unsigned decimal integer
o Unsigned octal
b Binary (base 2)
x Unsigned hexadecimal integer
X Unsigned hexadecimal integer (uppercase)
f Decimal floating point, lowercase
e Scientific notation (mantissa/exponent), lowercase
E Scientific notation (mantissa/exponent), uppercase
g Use the shortest representation: %e or %f
G Use the shortest representation: %E or %F
c Single character
s String of characters
y (or Y) SDI-12 compatible output. INF and NAN are output as 9999999
z (or Z) %m.nZ fits n significant digits into a width of m characters
% A % followed by another % character will write a single % to the stream

NOTE: If ‘L’ is specified before f, e, or g, then the value passed in is of type double and, therefore, the precision of double can be displayed. The maximum number of digits possible is 7 for floats (IEEE4, single precision) and 18 for doubles(IEEE8, double precision).

Width and precision may be specified directly in the format string or may be passed in from one of the arguments. When specifying width and/or precision as an argument their place should be indicated by an asterisks (*). The following examples are equivalent and will return a floating point value with a field width of at least 3 characters and a precision of 2 characters.

sprintf(dest,"%3.2f",67.89)

sprintf(dest,"%*.2f",3,67.89)

sprintf(dest,"%*.*f",3,2,67.89)

Precision for f specifies the number of digits after the decimal point, whereas precision for g and e specifies the total number of digits displayed, including digits before and after the decimal point.

For example:

sprintf(Str(6),"%.10Lf",112.000009R) prints 112.0000090000

sprintf(Str(8),"%.10Lg",112.000009R) prints 112.000009

Up to five Flags can be used immediately following the % sign:

Flag Description
+ Always denote the sign of a number
Space Prefixes a non-negative signed number with a space
- Left-align the output of the placeholder (default is to right-align)
# For g and G, trailing zeros are not removed. For f, e, g, or G, the output always contains a decimal point. For o, x, and X, prepend o, Ox, or OX to non-zero numbers
0 Use 0 spaces to pad a field when the width option is used

Type: Variable declared as a string

Argument1..Argument10

The arguments to pass into the format string. Up to 10 arguments can be entered. These arguments can be decimal values, integers, strings, variables, or expressions. The data type of these arguments must match the format specifier.

Usage notes:

Sprintf performs no data type conversions on the arguments passed into the format string. The format specifier must match the argument type or erroneous values are returned.

TableName.Timestamp by default is returned as an integer. To print a timestamp it must be placed inside an expression that forces it to be converted to a string.

Arguments from a data table that are stored as ClosedFP2 Two-byte floating-point data type. Default datalogger data type for stored data. While IEEE four-byte floating point is used for variables and internal calculations, FP2 is adequate for most stored data. FP2 provides three or four significant digits of resolution, and requires half the memory as IEEE4. are converted to floats before they are accessed. The precision for these values can be represented fairly closely by using %4.g, though if the mantissa is <1000 it is only 3 significant digits (i.e., %.3g).

For all options but y (or Y), infinity is output as ClosedINF A data word indicating the result of a function is infinite or undefined. and not a number ClosedNAN Not a number. A data word indicating a measurement or processing error. Voltage overrange, SDI-12 sensor error, and undefined mathematical results can produce NAN..

A formatted value can be padded with zeros (or spaces), using the notation %#code (right justified) or %-#code (left justified), where # is the number of spaces for the field. Consider the following examples, where the Long variable is 12345.

If FormatString = %8d the result is (space)(space)(space)12345

If FormatString = %-8d the result is 12345(space)(space)(space)

If FormatString = %08d the result is 00012345

If FormatString = %-08d the result is 12345000