tobase

Synopsis

$tobase(<base> <number>)

Technical

Converts an integer to a string in <base>, which must be from 2 through 36. Digits above nine are uppercase letters A through Z. No base prefix or padding is added. A leading minus sign is retained for ordinary negative input; zero returns 0.

Both arguments use function-word parsing and base-zero integer conversion: decimal is usual, leading zero selects octal, and 0x selects hexadecimal. Thus <number> is not limited to decimal input. Conversion accepts a numeric prefix before trailing text; nonnumeric input becomes zero. Additional words are ignored.

Practical

Use this function to convert integers to binary, octal, or hexadecimal. strtol converts text in a specified base to a decimal integer.

Returns

The converted string, or empty if an argument is missing or the parsed base is outside 2 through 36. An unconvertible number returns 0, which is indistinguishable from a valid zero.

The base is parsed as intmax_t then narrowed to C int before validation; avoid base arguments outside that type's range. Parsing overflow is not reported. A minus sign is handled specially only when it is the first character of the remaining number argument; use ordinary unquoted signed numeric text.

Restrictions

Although the input is stored in intmax_t, digit generation uses floating-point pow to determine lengths and divisors, then converts those powers back to integers. Large values can be rounded incorrectly; near integer limits, power conversion can exceed the signed range and make behavior undefined. This is not a reliable full-width integer converter. Use modest values whose powers and divisions are accurately representable, rather than assuming every intmax_t value is supported.

There are no options, settings, or server requirements.

Examples

$tobase(16 180099407)    Returns ABC194F.
$tobase(2 10)            Returns 1010.
$tobase(16 -255)         Returns -FF.
$tobase(10 010)          Returns 8.
$tobase(16 0)            Returns 0.
$tobase(1 10)            Returns the empty string.

History

First appeared in EPIC5-0.0.2.

Source

Handler: source/functions.c. Integer argument parsing: include/functions.h.