A64L(3) | Library Functions Manual | A64L(3) |
a64l
, l64a
— convert between 32-bit integer and radix-64 ASCII
string
#include
<stdlib.h>
long
a64l
(const
char *s);
char *
l64a
(long
value);
The
a64l
()
and l64a
() functions are used to maintain numbers
stored in radix-64 ASCII characters. This is a notation by which 32-bit
integers can be represented by up to six characters; each character
represents a “digit” in a radix-64 notation.
The characters used to represent digits are
‘.
’ for 0,
‘/
’ for 1,
‘0
’ through
‘9
’ for 2-11,
‘A
’ through
‘Z
’ for 12-37, and
‘a
’ through
‘z
’ for 38-63.
The
a64l
()
function takes a pointer to a null-terminated radix-64 representation and
returns a corresponding 32-bit value. If the string pointed to by
s contains more than six characters,
a64l
() will use the first six.
a64l
() scans the character string from left to
right, decoding each character as a 6-bit radix-64 number. If a long integer
is larger than 32 bits, the return value will be sign-extended.
l64a
()
takes a long integer argument value and returns a
pointer to the corresponding radix-64 representation.
On success, a64l
() returns a 32-bit
representation of s. If s is a
null pointer or if it contains digits other than those described above.
a64l
() returns -1 and sets the global variable
errno to EINVAL
.
On success, l64a
() returns a pointer to a
string containing the radix-64 representation of
value. If value is 0,
l64a
() returns a pointer to the empty string. If
value is negative, l64a
()
returns a null pointer and sets the global variable
errno to EINVAL
.
The value returned by
l64a
()
is a pointer into a static buffer, the contents of which will be overwritten
by subsequent calls.
The value returned by
a64l
() may
be incorrect if the value is too large; for that reason, only strings that
resulted from a call to l64a
() should be used to
call a64l
().
If a long integer is larger than 32 bits, only the low-order 32 bits are used.
The a64l
() and
l64a
() functions conform to X/Open
Portability Guide Issue 4, Version 2
(“XPG4.2”).
August 17, 1997 | macOS 14.6 |