strtol

Synopsis

$strtol(<base> <number>)

Technical

Converts <number> from the specified base to a decimal integer. <base> must be 0 or an integer from 2 through 36. Missing arguments or an unsupported base return the empty string. Both arguments use function-word parsing; additional arguments are ignored.

Base 0 detects the number's base: a leading 0x or 0X selects hexadecimal, a leading 0 selects octal, and other numbers use decimal. Some system libraries also recognize binary prefixes; use explicit base 2 with unprefixed binary digits for portability. Bases above ten use case-insensitive letters a through z as additional digits. An optional leading sign is accepted.

Conversion stops at the first character invalid for the base and returns the converted prefix. It returns 0 if there is no convertible prefix; it does not validate the entire word. For example, 12junk in base ten returns 12, while junk12 returns 0.

Practical

Use this function to convert binary, octal, or hexadecimal numbers to decimal. tobase converts a decimal integer to another base.

Returns

The converted value as a signed decimal integer. Conversion uses the system's intmax_t, rather than necessarily the narrower long type. Overflow returns INTMAX_MAX or INTMAX_MIN according to the sign; EPIC does not check errno, so these results cannot distinguish overflow from a valid boundary value. See the strtoimax specification.

The base itself is parsed using base-zero integer conversion before validation: 0x10 selects base 16, and nonnumeric base text parses as zero. That result is narrowed to C int; avoid out-of-range base arguments, whose narrowing is implementation-dependent. There are no settings or server requirements.

Examples

$strtol(16 ABC194F)    Returns 180099407.
$strtol(2 1010)        Returns 10.
$strtol(0 010)         Returns 8.
$strtol(10 12junk)     Returns 12.
$strtol(10 junk12)     Returns 0.
$strtol(1 10)         Returns the empty string.

History

First appeared in EPIC5-0.0.2.

Source

Handler: source/functions.c. Argument conversion and return formatting: include/functions.h.