a64l(3) — Linux manual page

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).
       ┌─────────────────────────┬───────────────┬─────────────────────┐
       │ 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)

COLOPHON         top

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Linux man-pages 6.9.1          2024-05-02                        a64l(3)

Pages that refer to this page: strtoul(3)

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