FUNCTION::ISDIGIT(3stap) A collection of standard strin FUNCTION::ISDIGIT(3stap)

# [NAME](#NAME)

function::isdigit - Checks for a digit

# [SYNOPSIS](#SYNOPSIS)

```


    isdigit:long(str:string)
```

# [ARGUMENTS](#ARGUMENTS)

*str*

string to check

# [DESCRIPTION](#DESCRIPTION)

Checks for a digit (0 through 9) as the first character of a string. Returns non-zero if true, and a zero if false.

# [SEE ALSO0](#SEE_ALSO0)

[*tapset::string*(3stap)](/man/enterprise-packages/systemtap/tapset::string.3stap)

September 2026 SystemTap Tapset Reference Ver

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Document: function::isdigit(3stap) from systemtap 5.6-r0 (Chainguard OS)
Source: https://sourceware.org/git/systemtap.git