A64L(3) BSD Library Functions Manual A64L(3)NAME
a64l, l64a, l64a_r — convert between a long integer and a base-64 ASCII
Standard C Library (libc, -lc)
a64l(const char *s);
l64a(long int l);
l64a_r(long int l, char *buffer, int buflen);
These functions are used to maintain numbers stored in radix-64 ASCII
characters. This is a notation by which 32-bit integers can be repre‐
sented by up to six characters; each character represents a digit in
radix-64 notation. If the type long contains more than 32 bits, only the
low-order 32 bits are used for these operations.
The characters used to represent “digits” are ‘.’ for 0, ‘/’ for 1, ‘0’ -
‘9’ for 2 - 11, ‘A’ - ‘Z’ for 12 - 37, and ‘a’ - ‘z’ for 38 - 63.
The a64l() function takes a pointer to a radix-64 representation, in
which the first digit is the least significant, and returns a correspond‐
ing long value. If the string pointed to by s contains more than six
characters, a64l() uses the first six. If the first six characters of
the string contain a null terminator, a64l() uses only characters preced‐
ing the null terminator. The a64l() function scans the character string
from left to right with the least significant digit on the left, decoding
each character as a 6-bit radix-64 number. If the type long contains
more than 32 bits, the resulting value is sign-extended. The behavior of
a64l() is unspecified if s is a null pointer or the string pointed to by
s was not generated by a previous call to l64a().
The l64a() function takes a long argument and returns a pointer to the
corresponding radix-64 representation. The behavior of l64a() is unspec‐
ified if value is negative.
The value returned by l64a() is a pointer into a static buffer. Subse‐
quent calls to l64a() may overwrite the buffer.
The l64a_r() function performs a conversion identical to that of l64a()
and stores the resulting representation in the memory area pointed to by
buffer, consuming at most buflen characters including the terminating NUL
On successful completion, a64l() returns the long value resulting from
conversion of the input string. If a string pointed to by s is an empty
string, a64l() returns 0.
The l64a() function returns a pointer to the radix-64 representation. If
value is 0, l64a() returns a pointer to an empty string.
The a64l(), l64a(), and l64a_r() functions are derived from NetBSD with
modifications. They appeared in FreeBSD 6.1.
The a64l(), l64a(), and l64a_r() functions were added to FreeBSD by Tom
Rhodes ⟨trhodes@FreeBSD.org⟩. Almost all of this manual page came from
the POSIX standard.
BSD November 20, 2005 BSD