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The order of the data blocks is not specified, so programs should look at the variable

names to decide which variable is currently being loaded.

The header

The file consists of a number of data blocks preceded by 20-byte headers. Each header

contains five 32-bit integers (as described in the table below).

Bytes

Value

0 – 3

Data format (0, 10 or 20)

4 – 7

Number of values

8 – 11

12 – 15

16 – 19

Name length

Data format

The ‘Data format’ in the first 4-bytes describes the type of numerical data in the array.

Value

Description

Double (64-bit floating point)

Single (32-bit floating point)

Integer (32-bit)

Number of values

The ‘Number of values’ is a 32-bit integer describing the number of numerical values

in the array. This value may be 1 for variables that only describe one value; but for

arrays of samples or times, expect this to be a large number.

Name length

The ‘Name length’ is the length of the name of the variable as a null-terminated 1-

byte per character ASCII string. The last null terminating character (‘\0’) is included in

the ‘Name length’ so if the variable name is “TStart” (same as ‘TStart\0’) then the

name length will be 7.

The data block

The data block begins with the name of the variable (such as A, Tinterval) and you

should read in the number of bytes described by the ‘Name length’ part of the header

(not forgetting that the last byte in the string is ‘\0’ if your programming language

needs to take account of this).

The remaining part of the data block is the actual data itself, so read in the number of

values described in the ‘Number of values’ part of the header. Remember to take

account of the size of each value as described in the ‘Data format’ part of the header.

Channel data such as voltages, in variables such as A and B, are stored as 32-bit

single-precision floating-point data types. Times such as Tstart, Tinterval and T are

stored as 64-bit double-precision floating-point data types. Length is stored as a 32-

bit integer.