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 argument 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)

COLOPHON

       This  page  is  part of release 5.13 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.

                                            2021-03-22                                    A64L(3)