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NAME
a64l, l64a — convert between a 32-bit integer and a radix-64 ASCII string
SYNOPSIS
#include <stdlib.h> long a64l(const char *s); char *l64a(long value);
DESCRIPTION
These functions 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 radix-64
notation. If the type long contains more than 32 bits, only the low-order 32 bits shall be used for these
operations.
The characters used to represent digits are '.' (dot) 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 shall take a pointer to a radix-64 representation, in which the first digit is the
least significant, and return the corresponding long value. If the string pointed to by s contains more
than six characters, a64l() shall use the first six. If the first six characters of the string contain a
null terminator, a64l() shall use only characters preceding the null terminator. The a64l() function
shall scan 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 shall take a long argument and return a pointer to the corresponding radix-64
representation. The behavior of l64a() is unspecified if value is negative.
The value returned by l64a() may be a pointer into a static buffer. Subsequent calls to l64a() may
overwrite the buffer.
The l64a() function need not be thread-safe.
RETURN VALUE
Upon successful completion, a64l() shall return the long value resulting from conversion of the input
string. If a string pointed to by s is an empty string, a64l() shall return 0L.
The l64a() function shall return a pointer to the radix-64 representation. If value is 0L, l64a() shall
return a pointer to an empty string.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
If the type long contains more than 32 bits, the result of a64l(l64a(x)) is x in the low-order 32 bits.
RATIONALE
This is not the same encoding as used by either encoding variant of the uuencode utility.
FUTURE DIRECTIONS
None.
SEE ALSO
strtoul()
The Base Definitions volume of POSIX.1‐2008, <stdlib.h>
The Shell and Utilities volume of POSIX.1‐2008, uuencode
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event
of any discrepancy between this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced
during the conversion of the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .