a64l(3) - Linux manual page (original) (raw)

a64l(3) Library Functions Manual a64l(3)

NAME top

   a64l, l64a - convert between long and base-64

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#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 >= 2.19: */ _DEFAULT_SOURCE
           || /* glibc <= 2.19: */ _SVID_SOURCE

DESCRIPTION top

   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 top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────┬───────────────┬─────────────────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────┼───────────────┼─────────────────────┤
   │ **l64a**()                   │ Thread safety │ MT-Unsafe race:l64a │
   ├──────────────────────────┼───────────────┼─────────────────────┤
   │ **a64l**()                   │ Thread safety │ MT-Safe             │
   └──────────────────────────┴───────────────┴─────────────────────┘

STANDARDS top

   POSIX.1-2008.

HISTORY top

   POSIX.1-2001.

NOTES top

   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 before glibc 2.2.5 (puts most
   significant digit first).

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

SEE ALSO top

   **uuencode**(1), [strtoul(3)](../man3/strtoul.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 a64l(3)

Pages that refer to this page:strtoul(3)