| SYNOPSIS | 
#include <dkim.h>
DKIM_STAT dkim_get_sigsubstring(
	DKIM *dkim,
	DKIM_SIGINFO *sig,
        char *buf,
        size_t *buflen
);
Retrieve a minimal substring of the actual signature (i.e. the "b=" tag
value) from a specified signature, of sufficient length to identify this
signature uniquely from others. | 
|---|
| DESCRIPTION | 
| Called When | dkim_getsig() is called after
    dkim_eom() when dkim is a
    verifying handle, i.e. one returned by an earlier call to
    dkim_verify(). |  | 
|---|
| ARGUMENTS | 
    | Argument | Description | 
|---|
 | dkim | Message-specific handle, returned by 
        dkim_sign(). |  | sig | Signature-specific handle, retrieved by a prior call to
            dkim_getsiglist(). |  | buf | Pointer to a buffer that should receive a minimal unique
	    substring of the digital signature portion of sig. |  | buflen | The address of an integer that should contain the number of
	    bytes available at buf and will be updated to contain
	    the number of bytes needed to produce a minimal substring. |  | 
|---|
| NOTES | 
No fewer than eight bytes will be requested.  If two or more signatures
    have the same initial byte sequences in "b=" tags, larger lengths will
    be required, theoretically requiring as much as the entire signature.
If the size of buf is too small to contain the minimal substring
    of sig, DKIM_STAT_NORESOURCE is returned, buflen
    will be updated to indicate the minimal number of bytes required,
    and buf will be unchanged.
The string written to buf will be NULL-terminated unless the
    provided buffer is exactly the right size to contain the output.
 |