vi

IN

Unique logical identifier to a session.

writeFmt

IN

String describing the format for arguments.

...

IN

Parameters to which the format string is applied.

VI_SUCCESS

Parameters were successfully formatted.

VI_ERROR_INV_OBJECT

The given session reference is invalid.

VI_ERROR_RSRC_LOCKED

Specified operation could not be performed because the resource identified by vi has been locked for this kind of access.

VI_ERROR_IO

Could not perform write operation because of I/O error.

VI_ERROR_TMO

Timeout expired before write operation completed.

VI_ERROR_INV_FMT

A format specifier in the writeFmt string is invalid.

VI_ERROR_NSUP_FMT

A format specifier in the writeFmt string is not supported.

VI_ERROR_ALLOC

The system could not allocate a formatted I/O buffer because of insufficient resources.

\n

Sends the ASCII LF character. The END identifier will also be automatically sent.

\r

Sends an ASCII CR character.

\t

Sends an ASCII TAB character.

\###

Sends the ASCII character specified by the octal value.

\x##

Sends the ASCII character specified by the hexadecimal value.

\"

Sends the ASCII double-quote (") character.

\\

Sends a backslash (\) character.

Modifier

An integer specifying field width.

d, f, s format codes

This specifies the minimum field width of the converted argument. If an argument is shorter than the field width, it will be padded on the left (or the right if the - flag is present).

Special case:

For the @H, @Q, and @B flags, the field width includes the #H, #Q, and #B strings, respectively.

An asterisk (*) may be present in lieu of a field width modifier, in which case an extra arg is used. This arg must be an integer representing the field width.

An integer specifying precision.

d, f, s format codes

The precision string consists of a string of decimal digits. A decimal point (.) must prefix the precision string. The precision string specifies the following:

1. The minimum number of digits to appear for the @1, @H, @Q, and @B flags and the i, o, u, x, and X format codes.
2. The maximum number of digits after the decimal point in case of f format codes.
3. The maximum numbers of characters for the string (s) specifier.
4. Maximum significant digits for g format code.

An asterisk (*) may be present in lieu of a precision modifier, in which case an extra arg is used. This arg must be an integer representing the precision of a numeric field.

An argument length modifier.

h, l, L, z, and Z are legal values. (z and Z are not ANSI C standard modifiers.)

h (d, b, B format codes)

l (d, f, b, B format codes)

L (f format code)

z (b, B format codes)

Z (b, B format codes)

The argument length modifiers specify one of the following:

1. The h modifier promotes the argument to a short or unsigned short, depending on the format code type.
2. The l modifier promotes the argument to a long or unsigned long.
3. The L modifier promotes the argument to a long double parameter.
4. The z modifier promotes the argument to an array of floats.
5. The Z modifier promotes the argument to an array of doubles.

A comma (,) followed by an integer n, where n represents the array size.

%d (plus variants) and %f only

The corresponding argument is interpreted as a reference to the first element of an array of size n. The first n elements of this list are printed in the format specified by the format code.

An asterisk (*) may be present after the comma (,) modifier, in which case an extra arg is used. This arg must be an integer representing the array size of the given type.

@1

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined NR1 compatible number, which is an integer without any decimal point (for example, 123).

@2

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined NR2 compatible number. The NR2 number has at least one digit after the decimal point (for example, 123.45).

@3

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined NR3 compatible number. An NR3 number is a floating point number represented in an exponential form (for example, 1.2345E-67).

@H

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined <HEXADECIMAL NUMERIC RESPONSE DATA>. The number is represented in a base of sixteen form. Only capital letters should represent numbers. The number is of form #HXXX.., where XXX.. is a hexadecimal number (for example, #HAF35B).

@Q

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined <OCTAL NUMERIC RESPONSE DATA>. The number is represented in a base of eight form. The number is of the form #QYYY.., where YYY.. is an octal number (for example, #Q71234).

@B

%d (plus variants) and %f only

Converts to an IEEE 488.2 defined <BINARY NUMERIC RESPONSE DATA>. The number is represented in a base two form. The number is of the form #BZZZ.., where ZZZ.. is a binary number (for example, #B011101001).

Default functionality

Print an integer in NR1 format (an integer without a decimal point).

@2 or @3

The integer is converted into a floating point number and output in the correct format.

field width

Minimum field width of the output number. Any of the six IEEE 488.2 modifiers can also be specified with field width.

Length modifier l

arg is a long integer.

Length modifier h

arg is a short integer.

,array size

arg points to an array of integers (or long or short integers, depending on the length modifier) of size array size. The elements of this array are separated by array size - 1 commas and output in the specified format.

Default functionality

Print a floating point number in NR2 format (a number with at least one digit after the decimal point).

@1

Print an integer in NR1 format. The number is truncated.

@3

Print a floating point number in NR3 format (scientific notation). Precision can also be specified.

field width

Minimum field width of the output number. Any of the six IEEE 488.2 modifiers can also be specified with field width.

Length modifier l

arg is a double float.

Length modifier L

arg is a long double.

,array size

arg points to an array of floats (or doubles or long doubles, depending on the length modifier) of size array size. The elements of this array are separated by array size - 1 commas and output in the specified format.

Default functionality

The data block is sent as an IEEE 488.2 <DEFINITE LENGTH ARBITRARY BLOCK RESPONSE DATA>. A count (long integer) must appear as a flag that specifies the number of elements (by default, bytes) in the block. A field width or precision modifier is not allowed with this format code.

* (asterisk)

An asterisk may be present instead of the count. In such a case, two args are used, the first of which is a long integer specifying the count of the number of elements in the data block. The second arg is a reference to the data block. The size of an element is determined by the optional length modifier (see below), and the default is byte width.

Length modifier h

arg points to an array of unsigned short integers (16 bits). The count corresponds to the number of words rather than bytes. The data is swapped and padded into standard IEEE 488.2 format, if native computer representation is different.

Length modifier l

arg points to an array of unsigned long integers. The count specifies the number of longwords (32 bits). Each longword data is swapped and padded into standard IEEE 488.2 format, if native computer representation is different.

Length modifier z

arg points to an array of floats. The count specifies the number of floating point numbers (32 bits). The numbers are represented in IEEE 754 format, if native computer representation is different.

Length modifier Z

arg points to an array of doubles. The count specifies the number of double floats (64 bits). The numbers will be represented in IEEE 754 format, if native computer representation is different.

Default functionality

The data block is sent as raw binary data. A count (long integer) must appear as a flag that specifies the number of elements (by default, bytes) in the block. A field width or precision modifier is not allowed with this format code.

* (asterisk)

An asterisk may be present instead of the count. In such a case, two args are used, the first of which is a long integer specifying the count of the number of elements in the data block. The second arg is a reference to the data block. The size of an element is determined by the optional length modifier (see below), and the default is byte width.

Length modifier h

arg points to an array of unsigned short integers (16 bits). The count corresponds to the number of words rather than bytes. If the optional !ol byte order modifier is present, the data is sent in little endian format; otherwise, the data is sent in standard IEEE 488.2 format. The data will be byte swapped and padded as appropriate if native computer representation is different.

Length modifier l

arg points to an array of unsigned long integers (32 bits). The count specifies the number of longwords rather than bytes. If the optional !ol byte order modifier is present, the data is sent in little endian format; otherwise, the data is sent in standard IEEE 488.2 format. The data will be byte swapped and padded as appropriate if native computer representation is different.

Length modifier z

arg points to an array of floats. The count specifies the number of floating-point numbers (32 bits). If the optional !ol modifier is present, the data is sent in little endian format; otherwise, the data sent in standard IEEE 488.2 format. The data will be byte swapped and padded as appropriate to native computer format.

Length modifier Z

arg points to an array of doubles. The count specifies the number of double floats (64 bits). If the optional !ol modifier is present, the data is sent in little endian format; otherwise, the data sent in standard IEEE 488.2 format. The data will be byte swapped and padded as appropriate to native computer format.

Byte order modifier !ob

Data is sent in standard IEEE 488.2 (big endian) format. This is the default behavior if neither !ob nor !ol is present.

Byte order modifier !ol

Data is sent in little endian format.