<div class="content"><p>The ListReaderGroups_Call structure contains the parameters
for the List Readers Groups call (for more information, see sections <a href="0fb90448-01e2-4da1-9d60-cfa1cc5e31a8" data-linktype="relative-path">3.1.4.5</a> and <a href="b9b6341e-c52c-4f02-af09-25e2121f0382" data-linktype="relative-path">3.1.4.6</a>).</p><dl>
<dd>
<div><pre> typedef struct _ListReaderGroups_Call {
   REDIR_SCARDCONTEXT Context;
   long fmszGroupsIsNULL;
   unsigned long cchGroups;
 } ListReaderGroups_Call;
</pre></div>
</dd></dl><p><b>Context:</b>  A valid context, as
specified in section <a href="060abee1-e520-4149-9ef7-ce79eb500a59" data-linktype="relative-path">2.2.1.1</a>.</p><p><b>fmszGroupsIsNULL:</b>  A Boolean value
specifying whether the caller wants to retrieve just the length of the data.
Set to FALSE (0x00000000) in order to allow the data to be returned. Set to
TRUE (0x00000001) and only the length of the data will be returned.</p><p><b>cchGroups:</b>  The length of the string
buffer specified by the caller. If <b>cchGroups</b> is set to
SCARD_AUTOALLOCATE with a value of 0xFFFFFFFF, a string of any length can be
returned. Otherwise, the returned string MUST NOT exceed <b>cchGroups</b>
characters in length, including any null characters. When the string to be
returned exceeds <b>cchGroups</b> characters in length, including any null
characters, <a href="6630bb5b-fc0e-4141-8b53-263225c7628d" data-linktype="relative-path">ListReaderGroups_Return</a>.<b>ReturnCode</b>
MUST be set to SCARD_E_INSUFFICIENT_BUFFER (0x80100008). The <b>cchGroups</b>
field MUST be ignored if <b>fmszGroupsIsNULL</b> is set to TRUE (0x00000001).
Also, if <b>fmszGroupsIsNULL</b> is set to FALSE (0x00000000) but <b>cchGroups</b>
is set to 0x00000000, then the call MUST succeed, ListReaderGroups_Return.<b>cBytes</b>
MUST be set to the length of the data, in bytes, and ListReaderGroups_Return.<b>msz</b>
MUST be set to NULL.</p></div>