The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


a64l, l64a - convert between a 32-bit integer and a radix-64 ASCII string


#include <stdlib.h>

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


These functions are used to 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 are used for these operations.

The characters used to represent `digits' are '.' 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 takes a pointer to a radix-64 representation, in which the first digit is the least significant, and returns a corresponding long value. If the string pointed to by s contains more than six characters, a64l() uses the first six. If the first six characters of the string contain a null terminator, a64l() uses only characters preceding the null terminator. The a64l() function scans 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 behaviour 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 takes a long argument and returns a pointer to the corresponding radix-64 representation. The behaviour 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() interface need not be reentrant. An interface that is not required to be reentrant is not required to be thread-safe.


On successful completion, a64l() returns the long value resulting from conversion of the input string. If a string pointed to by s is an empty string, a64l() returns 0L.

The l64a() function returns a pointer to the radix-64 representation. If value is 0L, l64a() returns a pointer to an empty string.


No errors are defined.




If the type long contains more than 32 bits, the result of a64l(l64a(x)) is x in the low-order 32 bits.




strtoul(), <stdlib.h>.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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