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typeof

Returns the Csound type of a variable or expression as a string.

Use typeof when you want to include a type name in a debug message or check it in a condition. The result describes the argument's type, regardless of its value.

Syntax

Stype = typeof(xarg)

Stype typeof xarg

Initialization

xarg is a variable or expression of any Csound type. Stype receives its internal type name at initialization. Passing a k-rate value or an audio signal does not make the opcode run on every control cycle.

Common results are shown below. Type names are case-sensitive.

Returned string Meaning
"i" An i-rate number
"k" A k-rate number
"a" An audio signal
"S" A string
"c" A numeric constant, such as 440
"p" A score p-field, such as p4
"[" An array

An array returns "[" without its element type, dimensions or length. To inspect an element of a nonempty array, use an expression such as typeof(iNotes[0]).

Other types return their internal names. For example, a user-defined structure named Note returns ":Note;".

The opcode returns a string and prints nothing by itself. Use printf or prints to display it, or strcmp to compare it with a type name.

Examples

This example checks whether a frequency control has type k, then prints the types of a note array and its first element. It uses typeof.csd.

Use type names in messages and conditions
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<CsoundSynthesizer>
<CsOptions>
-n -d -m0
</CsOptions>
<CsInstruments>
sr = 44100
ksmps = 32
nchnls = 1
0dbfs = 1

instr 1
  kFrequency init 440
  iNotes[] fillarray 60, 64, 67

  ; Save the type name so we can print it and compare it.
  SfrequencyType = typeof(kFrequency)
  printf_i "Frequency control has type %s\n", 1, SfrequencyType
  if strcmp(SfrequencyType, "k") == 0 then
    prints "The frequency control can change during a note\n"
  endif

  ; An array and an element of that array have different types.
  printf_i "Note array has type %s\n", 1, typeof(iNotes)
  printf_i "First note has type %s\n", 1, typeof(iNotes[0])

  ; A numeric literal has the constant type.
  printf_i "Literal 440 has type %s\n", 1, typeof(440)
endin
</CsInstruments>
<CsScore>
i 1 0 0.1
e
</CsScore>
</CsoundSynthesizer>

The output includes these lines.

Frequency control has type k
The frequency control can change during a note
Note array has type [
First note has type i
Literal 440 has type c

The final two lines show the difference between an i-rate array element and a numeric literal. Both hold numbers, but their internal types differ.

See also

Miscellaneous opcodes, strcmp, printf

Credits

Opcode by Victor Lazzarini, July 2025.

New in Csound 7.