A64L(3)                                                                 Linux Programmer's Manual                                                                A64L(3)

NAME
       a64l, l64a - convert between long and base-64

SYNOPSIS
       #include <stdlib.h>

       long a64l(const char *str64);
       char *l64a(long value);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       a64l(), l64a():
           _XOPEN_SOURCE >= 500
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc <= 2.19: */ _SVID_SOURCE

DESCRIPTION
       These  functions  provide a conversion between 32-bit long integers and little-endian base-64 ASCII strings (of length zero to six).  If the string used as argu‐
       ment for a64l() has length greater than six, only the first six bytes are used.  If the type long has more than 32 bits, then l64a() uses only the low  order  32
       bits of value, and a64l() sign-extends its 32-bit result.

       The 64 digits in the base-64 system are:

              '.'  represents a 0
              '/'  represents a 1
              0-9  represent  2-11
              A-Z  represent 12-37
              a-z  represent 38-63

       So 123 = 59*64^0 + 1*64^1 = "v/".

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────────────────┐
       │Interface                                                                                                                 │ Attribute     │ Value               │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────────────────┤
       │l64a()                                                                                                                    │ Thread safety │ MT-Unsafe race:l64a │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────────────────┤
       │a64l()                                                                                                                    │ Thread safety │ MT-Safe             │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────────────────┘

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

NOTES
       The value returned by l64a() may be a pointer to a static buffer, possibly overwritten by later calls.

       The behavior of l64a() is undefined when value is negative.  If value is zero, it returns an empty string.

       These functions are broken in glibc before 2.2.5 (puts most significant digit first).

       This is not the encoding used by uuencode(1).

SEE ALSO
       uuencode(1), strtoul(3)

                                                                               2021-03-22                                                                        A64L(3)