---
name: "Tcl_GetIntFromObj"
section: "3"
platform: "linux"
package: "tcl"
version: "8.6.16-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Tcl_GetBignumFromObj"
---

# Tcl\_GetIntFromObj(3)

manipulate Tcl values as integers

Part of [Tcl\_GetBignumFromObj(3)](/Tcl_GetBignumFromObj/3.md).

```

```

## NAME

Tcl\_NewIntObj, Tcl\_NewLongObj, Tcl\_NewWideIntObj, Tcl\_SetIntObj, Tcl\_SetLongObj, Tcl\_SetWideIntObj, Tcl\_GetIntFromObj, Tcl\_GetLongFromObj, Tcl\_GetWideIntFromObj, Tcl\_NewBignumObj, Tcl\_SetBignumObj, Tcl\_GetBignumFromObj, Tcl\_TakeBignumFromObj - manipulate Tcl values as integers

## SYNOPSIS

```
#include <tcl.h>

Tcl_Obj *
Tcl_NewIntObj(intValue)

Tcl_Obj *
Tcl_NewLongObj(longValue)

Tcl_Obj *
Tcl_NewWideIntObj(wideValue)

Tcl_SetIntObj(objPtr, intValue)

Tcl_SetLongObj(objPtr, longValue)

Tcl_SetWideIntObj(objPtr, wideValue)

int
Tcl_GetIntFromObj(interp, objPtr, intPtr)

int
Tcl_GetLongFromObj(interp, objPtr, longPtr)

int
Tcl_GetWideIntFromObj(interp, objPtr, widePtr)

#include <tclTomMath.h>

Tcl_Obj *
Tcl_NewBignumObj(bigValue)

Tcl_SetBignumObj(objPtr, bigValue)

int
Tcl_GetBignumFromObj(interp, objPtr, bigValue)

int
Tcl_TakeBignumFromObj(interp, objPtr, bigValue)

int
Tcl_InitBignumFromDouble(interp, doubleValue, bigValue)
```

## ARGUMENTS

- int *intValue* (in)

  Integer value used to initialize or set a Tcl value.

- long *longValue* (in)

  Long integer value used to initialize or set a Tcl value.

- Tcl\_WideInt *wideValue* (in)

  Wide integer value used to initialize or set a Tcl value.

- Tcl\_Obj *\*objPtr* (in/out)

  For **Tcl\_SetIntObj**, **Tcl\_SetLongObj**, **Tcl\_SetWideIntObj**, and **Tcl\_SetBignumObj**, this points to the value in which to store an integral value.  For **Tcl\_GetIntFromObj**, **Tcl\_GetLongFromObj**, **Tcl\_GetWideIntFromObj**, **Tcl\_GetBignumFromObj**, and **Tcl\_TakeBignumFromObj**, this refers to the value from which to retrieve an integral value.

- Tcl\_Interp *\*interp* (in/out)

  When non-NULL, an error message is left here when integral value retrieval fails.

- int *\*intPtr* (out)

  Points to place to store the integer value retrieved from *objPtr*.

- long *\*longPtr* (out)

  Points to place to store the long integer value retrieved from *objPtr*.

- Tcl\_WideInt *\*widePtr* (out)

  Points to place to store the wide integer value retrieved from *objPtr*.

- mp\_int *\*bigValue* (in/out)

  Points to a multi-precision integer structure declared by the LibTomMath library.

- double *doubleValue* (in)

  Double value from which the integer part is determined and used to initialize a multi-precision integer value.

  ```

  ```

## DESCRIPTION

These procedures are used to create, modify, and read Tcl values that hold integral values.

The different routines exist to accommodate different integral types in C with which values might be exchanged.  The C integral types for which Tcl provides value exchange routines are **int**, **long int**, **Tcl\_WideInt**, and **mp\_int**.  The **int** and **long int** types are provided by the C language standard.  The **Tcl\_WideInt** type is a typedef defined to be whatever signed integral type covers at least the 64-bit integer range (-9223372036854775808 to 9223372036854775807).  Depending on the platform and the C compiler, the actual type might be **long int**, **long long int**, **\_\_int64**, or something else. The **mp\_int** type is a multiple-precision integer type defined by the LibTomMath multiple-precision integer library.

The **Tcl\_NewIntObj**, **Tcl\_NewLongObj**, **Tcl\_NewWideIntObj**, and **Tcl\_NewBignumObj** routines each create and return a new Tcl value initialized to the integral value of the argument.  The returned Tcl value is unshared.

The **Tcl\_SetIntObj**, **Tcl\_SetLongObj**, **Tcl\_SetWideIntObj**, and **Tcl\_SetBignumObj** routines each set the value of an existing Tcl value pointed to by *objPtr* to the integral value provided by the other argument.  The *objPtr* argument must point to an unshared Tcl value.  Any attempt to set the value of a shared Tcl value violates Tcl's copy-on-write policy.  Any existing string representation or internal representation in the unshared Tcl value will be freed as a consequence of setting the new value.

The **Tcl\_GetIntFromObj**, **Tcl\_GetLongFromObj**, **Tcl\_GetWideIntFromObj**, **Tcl\_GetBignumFromObj**, and **Tcl\_TakeBignumFromObj** routines attempt to retrieve an integral value of the appropriate type from the Tcl value *objPtr*.  If the attempt succeeds, then **TCL\_OK** is returned, and the value is written to the storage provided by the caller.  The attempt might fail if *objPtr* does not hold an integral value, or if the value exceeds the range of the target type.  If the attempt fails, then **TCL\_ERROR** is returned, and if *interp* is non-NULL, an error message is left in *interp*.  The **Tcl\_ObjType** of *objPtr* may be changed to make subsequent calls to the same routine more efficient. Unlike the other functions, **Tcl\_TakeBignumFromObj** may set the content of the Tcl value *objPtr* to an empty string in the process of retrieving the multiple-precision integer value.

The choice between **Tcl\_GetBignumFromObj** and **Tcl\_TakeBignumFromObj** is governed by how the caller will continue to use *objPtr*.  If after the **mp\_int** value is retrieved from *objPtr*, the caller will make no more use of *objPtr*, then using **Tcl\_TakeBignumFromObj** permits Tcl to detect when an unshared *objPtr* permits the value to be moved instead of copied, which should be more efficient. If anything later in the caller requires *objPtr* to continue to hold the same value, then **Tcl\_GetBignumFromObj** must be chosen.

The **Tcl\_InitBignumFromDouble** routine is a utility procedure that extracts the integer part of *doubleValue* and stores that integer value in the **mp\_int** value *bigValue*.

## SEE ALSO

Tcl\_NewObj, Tcl\_DecrRefCount, Tcl\_IncrRefCount, Tcl\_GetObjResult

## KEYWORDS

integer, integer value, integer type, internal representation, value, value type, string representation