---
name: "gd_framenum_subset64"
section: "3"
platform: "linux"
package: "libgetdata-doc"
version: "0.11.0-15"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/gd_framenum_subset64"
---

# gd\_framenum\_subset64(3)

perform a reverse look-up on a monotonic Dirfile field, with largefile support.

## NAME

gd\_framenum\_subset64 — perform a reverse look-up on a monotonic Dirfile field, with largefile support.

## SYNOPSIS

**#define GD\_64BIT\_API**\
 **#include \<getdata.h\>**

**double gd\_framenum\_subset64(DIRFILE \****dirfile***,** **const char \****field\_code***, double** *value***, gd\_off64\_t** *field\_start***,** **gd\_off64\_t** *field\_end***);**

## DESCRIPTION

This version of [**gd\_framenum\_subset**(3)](/gd_framenum_subset/3.md) uses a 64-bit offset type (**gd\_off64\_t**), where one is available, regardless of the size of **off\_t**. It is only guaranteed to be available if **GD\_64BIT\_API** is defined before including getdata.h.

If **off\_t** is a 64-bit type, this function will the same as [**gd\_framenum\_subset**(3)](/gd_framenum_subset/3.md). Otherwise, [**gd\_framenum\_subset**(3)](/gd_framenum_subset/3.md) will be a version of this function which uses a 32-bit **off\_t**.

## SEE ALSO

[**gd\_framenum\_subset**(3)](/gd_framenum_subset/3.md), [**feature\_test\_macros**(7)](/feature_test_macros/7.md)