Unicode C
Unicode C
PC/SC Wait for Smart Card Status Change (Inserted, Removed from Reader, etc.)
See more SCard Examples
Demonstrates how to synchronously wait for a status change, such as for a smart card to be inserted into a reader, or removed from a reader.Note: This functionality was introduced in Chilkat v9.5.0.87.
Chilkat Unicode C Downloads
#include <C_CkSCardW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkStringBuilderW.h>
#include <C_CkStringTableW.h>
void ChilkatSample(void)
{
BOOL success;
HCkSCardW scard;
HCkJsonObjectW json;
const wchar_t *name;
HCkStringBuilderW sbState;
int i;
int count_i;
HCkStringTableW stReaders;
int numReaders;
HCkJsonObjectW json2;
BOOL changed;
const wchar_t *state;
const wchar_t *atr;
int numChanged;
success = FALSE;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
scard = CkSCardW_Create();
// First establish a context to the PC/SC Resource Manager
success = CkSCardW_EstablishContext(scard,L"user");
if (success == FALSE) {
wprintf(L"%s\n",CkSCardW_lastErrorText(scard));
CkSCardW_Dispose(scard);
return;
}
// First we'll examine the state of all connected readers to see which have smartcards already inserted..
// Get JSON containing information about the smartcards currently inserted into readers.
// This also includes information about USB security tokens.
json = CkJsonObjectW_Create();
success = CkSCardW_FindSmartcards(scard,json);
if (success == FALSE) {
wprintf(L"%s\n",CkSCardW_lastErrorText(scard));
CkSCardW_Dispose(scard);
CkJsonObjectW_Dispose(json);
return;
}
// When writing this example, I have 3 smart card readers plugged into my system.
// One of them has a smart card inserted.
// Here's the JSON returned by FindSmartcards...
// {
// "reader": [
// {
// "name": "Alcor Micro USB Smart Card Reader 0",
// "state": "empty"
// },
// {
// "name": "Generic Smart Card Reader Interface 0",
// "state": "present",
// "vendorName": "Generic",
// "serialNumber": "3230303730383138303030303030303030",
// "systemName": "Generic Smart Card Reader Interface 0",
// "card": {
// "atr": "3BFC180000813180459067464A00641606F2727E00E0",
// "windows": {
// "miniDriver": "tagliov70px.dll",
// "cryptoProvider": "Microsoft Base Smart Card Crypto Provider",
// "keyStorageProvider": "Microsoft Smart Card Key Storage Provider"
// }
// }
// },
// {
// "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
// "state": "empty"
// }
// ]
// }
CkJsonObjectW_putEmitCompact(json,FALSE);
wprintf(L"%s\n",CkJsonObjectW_emit(json));
wprintf(L" \n");
// We can iterate over the JSON to find the readers with a smart card already inserted..
sbState = CkStringBuilderW_Create();
i = 0;
count_i = CkJsonObjectW_SizeOfArray(json,L"reader");
while (i < count_i) {
CkJsonObjectW_putI(json,i);
name = CkJsonObjectW_stringOf(json,L"reader[i].name");
CkStringBuilderW_Clear(sbState);
CkJsonObjectW_StringOfSb(json,L"reader[i].state",sbState);
if (CkStringBuilderW_Contains(sbState,L"present",TRUE) == TRUE) {
wprintf(L"%s has a smart card inserted.\n",name);
}
else {
wprintf(L"%s does not have a smart card inserted.\n",name);
}
i = i + 1;
}
wprintf(L" \n");
// Now let's begin the code to wait for a change (where a smart card gets inserted or removed)
// Get the list of all readers.
stReaders = CkStringTableW_Create();
success = CkSCardW_ListReaders(scard,stReaders);
if (success == FALSE) {
wprintf(L"%s\n",CkSCardW_lastErrorText(scard));
CkSCardW_Dispose(scard);
CkJsonObjectW_Dispose(json);
CkStringBuilderW_Dispose(sbState);
CkStringTableW_Dispose(stReaders);
return;
}
// Show the reader names..
numReaders = CkStringTableW_getCount(stReaders);
i = 0;
while (i < numReaders) {
wprintf(L"%d: %s\n",i,CkStringTableW_stringAt(stReaders,i));
i = i + 1;
}
// Sample output from the above loop.
// 0: Alcor Micro USB Smart Card Reader 0
// 1: Generic Smart Card Reader Interface 0
// 2: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
//
// Synchronously wait 30 seconds for a card to be inserted or removed from any of the above readers.
json2 = CkJsonObjectW_Create();
success = CkSCardW_GetStatusChange(scard,30000,stReaders,json2);
if (success == FALSE) {
wprintf(L"%s\n",CkSCardW_lastErrorText(scard));
CkSCardW_Dispose(scard);
CkJsonObjectW_Dispose(json);
CkStringBuilderW_Dispose(sbState);
CkStringTableW_Dispose(stReaders);
CkJsonObjectW_Dispose(json2);
return;
}
wprintf(L" \n");
// Let's see what happened...
CkJsonObjectW_putEmitCompact(json2,FALSE);
wprintf(L"%s\n",CkJsonObjectW_emit(json2));
wprintf(L" \n");
// This is what json2 contains.
// A card was inserted into the reader named "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0"
// The "numChanged" indicates that one reader's status changed.
// The "changed":true indicates the reader that changed. The state is now "present".
// {
// "numChanged": 1,
// "reader": [
// {
// "name": "Alcor Micro USB Smart Card Reader 0",
// "changed": false,
// "state": "empty"
// },
// {
// "name": "Generic Smart Card Reader Interface 0",
// "changed": false,
// "state": "present",
// "atr": "3BFC180000813180459067464A00641606F2727E00E0"
// },
// {
// "name": "SCM Microsystems Inc. SCR33x USB Smart Card Reader 0",
// "changed": true,
// "state": "present",
// "atr": "3BDF96FF8131FE455A018048494443313158587300011B09"
// }
// ]
// }
// Find the reader that changed...
numChanged = CkJsonObjectW_IntOf(json2,L"numChanged");
wprintf(L"number of readers with a changed state: %d\n",numChanged);
i = 0;
count_i = CkJsonObjectW_SizeOfArray(json2,L"reader");
while (i < count_i) {
CkJsonObjectW_putI(json2,i);
changed = CkJsonObjectW_BoolOf(json2,L"reader[i].changed");
if (changed == TRUE) {
name = CkJsonObjectW_stringOf(json2,L"reader[i].name");
state = CkJsonObjectW_stringOf(json2,L"reader[i].state");
wprintf(L"Changed: \n");
wprintf(L" reader name: %s\n",name);
wprintf(L" new state: %s\n",state);
// If a card is now in this reader, we should have the ATR of the card..
if (CkJsonObjectW_HasMember(json2,L"reader[i].atr") == TRUE) {
atr = CkJsonObjectW_stringOf(json2,L"reader[i].atr");
wprintf(L" ATR of card inserted into this reader: %s\n",atr);
}
}
i = i + 1;
}
// The output from the above loop:
// number of readers with a changed state: 1
// Changed:
// reader name: SCM Microsystems Inc. SCR33x USB Smart Card Reader 0
// new state: present
// ATR of card inserted into this reader: 3BDF96FF8131FE455A018048494443313158587300011B09
// Applications should always release the context when finished.
success = CkSCardW_ReleaseContext(scard);
if (success == FALSE) {
wprintf(L"%s\n",CkSCardW_lastErrorText(scard));
}
CkSCardW_Dispose(scard);
CkJsonObjectW_Dispose(json);
CkStringBuilderW_Dispose(sbState);
CkStringTableW_Dispose(stReaders);
CkJsonObjectW_Dispose(json2);
}