I'm getting ridiculous behavior from RIDI_DEVICENAME. According to the documentation,
Return value
Type: UINT
If successful, this function returns a non-negative number indicating the number of bytes copied to pData.
If pData is not large enough for the data, the function returns -1. If pData is NULL, the function returns a value of zero. In both of these cases, pcbSize is set to the minimum size required for the pData buffer.
Call GetLastError to identify any other errors.
Ignoring the obvious problem that -1 is not a representable value in the UINT return type, it seems that the function should tell me the required size of the buffer, and if I supply a buffer of this size, the function should either succeed or at least follow its own rules for failure.
However, I'm not seeing this at all. On Windows 10, the Unicode version of the function sets pcbSize to 1 when pData is null and leaves it alone otherwise, failing in all cases. The ANSI version of the function sets pcbSize to 2 when pData is null, and otherwise doubles whatever value was passed in, and still fails.
Headers used for either version of test code:
#define WIN32_EXTRA_LEAN 1
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
#include <windows.h>
ANSI test code:
std::string GetRawInputDeviceName( HANDLE hRaw )
{
UINT numChars = 0u;
INT validChars;
validChars = static_cast<INT>(::GetRawInputDeviceInfoA(hRaw, RIDI_DEVICENAME, nullptr, &numChars));
auto lasterror = ::GetLastError();
if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
std::wcerr << L"Failed to get length of name of raw input device, retcode = " << validChars << L", last error = " << lasterror << L"\n";
return {};
}
std::string name;
name.resize(numChars);
validChars = static_cast<INT>(::GetRawInputDeviceInfoA(hRaw, RIDI_DEVICENAME, &name[0], &numChars));
lasterror = ::GetLastError();
if (validChars > 0) {
name.resize(validChars);
return name;
}
else {
std::wcerr << L"Failed to get name of raw input device, retcode = " << validChars << L", last error = " << lasterror << L"\n";
return {};
}
}
Unicode test code:
std::wstring GetRawInputDeviceName( HANDLE hRaw )
{
UINT numChars = 0u;
INT validChars;
validChars = static_cast<INT>(::GetRawInputDeviceInfoW(hRaw, RIDI_DEVICENAME, nullptr, &numChars));
auto lasterror = ::GetLastError();
if (lasterror != ERROR_INSUFFICIENT_BUFFER) {
std::wcerr << L"Failed to get length of name of raw input device, retcode = " << validChars << L", last error = " << lasterror << L"\n";
return {};
}
std::wstring name;
name.resize(numChars);
validChars = static_cast<INT>(::GetRawInputDeviceInfoW(hRaw, RIDI_DEVICENAME, &name[0], &numChars));
lasterror = ::GetLastError();
if (validChars > 0) {
name.resize(validChars);
return name;
}
else {
std::wcerr << L"Failed to get name of raw input device, retcode = " << validChars << L", last error = " << lasterror << L"\n";
return {};
}
}
On Windows 10 through RDP I'm getting ERROR_INSUFFICIENT_BUFFER consistently.
On Windows 8.1 running as a local user, I get ERROR_INSUFFICIENT_BUFFER if pData is null, and when I provide a buffer I get back failure ((UINT)-1) and GetLastError() returns zero.
I've also just tried proposing a likely-large-enough buffer size, and got failures as well.
What is going on, what is the right way to get the interface path name, and do I need administrative rights or to call some other APIs first? I don't seem to be having any problems calling GetRawInputDeviceList or using RIDI_DEVICEINFO mode of GetRawInputDeviceInfo... but I need the interface path in order to go further.
Windows HID Device Name Format
https://stackoverflow.com/a/64320052/103167
the GetRawInputDeviceName have several errors in declaration / implementation / documentation
by fact more correct declare return value as signed ( LONG or INT) but not UINT
exist 3 case:
1. function return negative value (or if want -1) : this is error
case, and by design - last error must be set. but really it not
always set (implementation error).
most common errors:
pcbSize or pData point to invalid or read only memory location. usual error in this case ERROR_NOACCESS (translated from
STATUS_ACCESS_VIOLATION)
hDevice not valid handle - ERROR_INVALID_HANDLE is returned
uiCommand not valid RIDI_XXX constant - ERROR_INVALID_PARAMETER
*pcbSize is not large enough for the data - in this case *pcbSize is set to the minimum size required for the pData buffer. ERROR_INSUFFICIENT_BUFFER
again - only in this case (-1) exist sense call GetLastError();
2. function return 0 this possible only in case when pData is NULL.
*pcbSize is set to the minimum size required for the pData buffer.
3. function return positive value ( > 0) this mean that this count of
bytes (in case RIDI_PREPARSEDDATA or RIDI_DEVICEINFO ) or
characters (in case RIDI_DEVICENAME) written to buffer
so documentation is wrong here:
pcbSize
[in, out]
Pointer to a variable that contains the size, in bytes, of the data in
pData.
in case RIDI_DEVICENAME in characters
so already visible very serious problems with design (type of return value - unsigned) and mixed bytes/characters. many different cases.
but then exist critical error in implementation. in begin of function handle hDevice converted to pointer.
PDEVICEINFO pDeviceInfo = HMValidateHandle(hDevice, TYPE_DEVICEINFO);
(if 0 returned - we got -1 on exit with ERROR_INVALID_HANDLE).
in DEVICEINFO exist UNICODE_STRING ustrName - this name and copied to user mode
switch (uiCommand) {
case RIDI_DEVICENAME:
/*
* N.b. UNICODE_STRING counts the length by the BYTE count, not by the character count.
* Our APIs always treat the strings by the character count. Thus, for RIDI_DEVICNAME
* only, cbOutSize holds the character count, not the byte count, in spite of its
* name. Confusing, but cch is the way to be consistent.
*/
cbOutSize = pDeviceInfo->ustrName.Length / sizeof(WCHAR) + 1; // for Null terminator
break;
//...
}
required cbOutSize compared with cbBufferSize = *pcbSize;
and if (cbBufferSize >= cbOutSize) api begin copy operation
exist next code
case RIDI_DEVICENAME:
if (cbOutSize <= 2) { // !!!! error !!!!
retval = -1;
goto leave;
}
RtlCopyMemory(pData, pDeviceInfo->ustrName.Buffer, pDeviceInfo->ustrName.Length);
((WCHAR*)pData)[1] = '\\'; // convert nt prefix ( \??\ ) to win32 ( \\?\ )
((WCHAR*)pData)[cbOutSize - 1] = 0; // make it null terminated
break;
cbOutSize here - is (len + 1) of device name (which we not control). so if name is zero length - always -1 is returned (error #1) but last error not set ( error #2 )
of course exist and error #3 - why is device name is 0 length ? this must not be. but in case terminal service devices - (virtual mouse/ keyboard device created on UMB bus ) - exist this result.
full code for api ( in kernel)
UINT NtUserGetRawInputDeviceInfo(
HANDLE hDevice,
UINT uiCommand,
LPVOID pData,
PUINT pcbSize)
{
UINT cbOutSize = 0;
UINT cbBufferSize;
int retval = 0;
EnterCrit(0, UserMode);
UserAtomicCheck uac;
try {
ProbeForRead(pcbSize, sizeof(UINT), sizeof(DWORD));
cbBufferSize = *pcbSize;
} except (EXCEPTION_EXECUTE_HANDLER) {
UserSetLastError(RtlNtStatusToDosError(GetExceptionCode()));// ERROR_NOACCESS
retval = -1;
goto leave1;
}
EnterDeviceInfoListCrit_();
PDEVICEINFO pDeviceInfo = HMValidateHandle(hDevice, TYPE_DEVICEINFO);
if (pDeviceInfo == NULL) {
UserSetLastError(ERROR_INVALID_HANDLE);
retval = -1;
goto leave;
}
/*
* Compute the size of the output and evaluate the uiCommand.
*/
switch (uiCommand) {
case RIDI_PREPARSEDDATA:
if (pDeviceInfo->type == DEVICE_TYPE_HID) {
cbOutSize = pDeviceInfo->hid.pHidDesc->hidCollectionInfo.DescriptorSize;
} else {
cbOutSize = 0;
}
break;
case RIDI_DEVICENAME:
/*
* N.b. UNICODE_STRING counts the length by the BYTE count, not by the character count.
* Our APIs always treat the strings by the character count. Thus, for RIDI_DEVICNAME
* only, cbOutSize holds the character count, not the byte count, in spite of its
* name. Confusing, but cch is the way to be consistent.
*/
cbOutSize = pDeviceInfo->ustrName.Length / sizeof(WCHAR) + 1; // for Null terminator
break;
case RIDI_DEVICEINFO:
cbOutSize = sizeof(RID_DEVICE_INFO);
break;
default:
UserSetLastError(ERROR_INVALID_PARAMETER);
retval = -1;
goto leave;
}
if (pData == NULL) {
/*
* The app wants to get the required size.
*/
try {
ProbeForWrite(pcbSize, sizeof(UINT), sizeof(DWORD));
*pcbSize = cbOutSize;
} except (EXCEPTION_EXECUTE_HANDLER) {
UserSetLastError(RtlNtStatusToDosError(GetExceptionCode()));// ERROR_NOACCESS
retval = -1;
goto leave;
}
retval = 0;
} else {
if (cbBufferSize >= cbOutSize) {
try {
ProbeForWrite(pData, cbBufferSize, sizeof(DWORD));
switch (uiCommand) {
case RIDI_PREPARSEDDATA:
if (pDeviceInfo->type == DEVICE_TYPE_HID) {
RtlCopyMemory(pData, pDeviceInfo->hid.pHidDesc->pPreparsedData, cbOutSize);
}
break;
case RIDI_DEVICENAME:
if (cbOutSize <= 2) { // !!!!
retval = -1;
goto leave;
}
RtlCopyMemory(pData, pDeviceInfo->ustrName.Buffer, pDeviceInfo->ustrName.Length);
((WCHAR*)pData)[1] = '\\'; // make it null terminated
((WCHAR*)pData)[cbOutSize - 1] = 0; // make it null terminated
break;
case RIDI_DEVICEINFO:
{
PRID_DEVICE_INFO prdi = (PRID_DEVICE_INFO)pData;
ProbeForRead(prdi, sizeof(UINT), sizeof(DWORD));
if (prdi->cbSize != cbOutSize) {
MSGERRORCLEANUP(ERROR_INVALID_PARAMETER);
}
ProbeForWrite(prdi, sizeof(RID_DEVICE_INFO), sizeof(DWORD));
RtlZeroMemory(prdi, sizeof(RID_DEVICE_INFO));
prdi->cbSize = cbOutSize;
switch (pDeviceInfo->type) {
case DEVICE_TYPE_HID:
prdi->dwType = RIM_TYPEHID;
prdi->hid.dwVendorId = pDeviceInfo->hid.pHidDesc->hidCollectionInfo.VendorID;
prdi->hid.dwProductId = pDeviceInfo->hid.pHidDesc->hidCollectionInfo.ProductID;
prdi->hid.dwVersionNumber = pDeviceInfo->hid.pHidDesc->hidCollectionInfo.VersionNumber;
prdi->hid.usUsagePage = pDeviceInfo->hid.pHidDesc->hidpCaps.UsagePage;
prdi->hid.usUsage = pDeviceInfo->hid.pHidDesc->hidpCaps.Usage;
break;
case DEVICE_TYPE_MOUSE:
prdi->dwType = RIM_TYPEMOUSE;
prdi->mouse.dwId = pDeviceInfo->mouse.Attr.MouseIdentifier;
prdi->mouse.dwNumberOfButtons = pDeviceInfo->mouse.Attr.NumberOfButtons;
prdi->mouse.dwSampleRate = pDeviceInfo->mouse.Attr.SampleRate;
break;
case DEVICE_TYPE_KEYBOARD:
prdi->dwType = RIM_TYPEKEYBOARD;
prdi->keyboard.dwType = GET_KEYBOARD_DEVINFO_TYPE(pDeviceInfo);
prdi->keyboard.dwSubType = GET_KEYBOARD_DEVINFO_SUBTYPE(pDeviceInfo);
prdi->keyboard.dwKeyboardMode = pDeviceInfo->keyboard.Attr.KeyboardMode;
prdi->keyboard.dwNumberOfFunctionKeys = pDeviceInfo->keyboard.Attr.NumberOfFunctionKeys;
prdi->keyboard.dwNumberOfIndicators = pDeviceInfo->keyboard.Attr.NumberOfIndicators;
prdi->keyboard.dwNumberOfKeysTotal = pDeviceInfo->keyboard.Attr.NumberOfKeysTotal;
break;
}
}
break;
default:
__assume(false);
}
} except (EXCEPTION_EXECUTE_HANDLER) {
UserSetLastError(RtlNtStatusToDosError(GetExceptionCode()));// ERROR_NOACCESS
retval = -1;
goto leave;
}
retval = cbOutSize;
} else {
/*
* The buffer size is too small.
* Returns error, storing the required size in *pcbSize.
*/
retval = -1;
try {
ProbeForWrite(pcbSize, sizeof(UINT), sizeof(DWORD));
*pcbSize = cbOutSize;
UserSetLastError(ERROR_INSUFFICIENT_BUFFER);
} except (EXCEPTION_EXECUTE_HANDLER) {
UserSetLastError(RtlNtStatusToDosError(GetExceptionCode()));// ERROR_NOACCESS
retval = -1;
goto leave;
}
}
}
leave:
LeaveDeviceInfoListCrit_();
leave1:
UserSessionSwitchLeaveCrit();
return retval;
}
then GetRawInputDeviceInfoA add additional errors compare GetRawInputDeviceInfoW - the value from *pcbSize by some reason multiple on 2. but again - this error in all case.
note that DeviceName (formatted from strings returned from driver on IRP_MN_QUERY_ID have very strict restrictions:
If a driver returns an ID with an illegal character, the system will
bug check. Characters with the following values are illegal in an ID
for this IRP:
Less than or equal to 0x20 (' ')
Greater than 0x7F
Equal to 0x2C (',')
so even after covert unicode to ansi - length of device name will be the same ( all symbols < 0x80 ). so not need *2 buffer size for Ansi version.
then i already view error in your code - you call ::GetLastError(); unconditionally after GetRawInputDeviceInfoW - but returned value have sense only in case api return -1
explain for observed behavior:
for local devices api in general work correct (if no mistakes in our code)
for terminal service devices - was 0 length ustrName. as result if we pass NULL in pData - return value will be
pDeviceInfo->ustrName.Length / sizeof(WCHAR) + 1;
because pDeviceInfo->ustrName.Length == 0 - 1 will be returned inside *pcbSize
in case A version - -by mistake - 2*1==2 will be returned.
but when e pass not NULL in pData - we trap in this
if (cbOutSize <= 2) { // !!!! error !!!!
retval = -1;
goto leave;
}
so you can pass any by size buffer, anyway, because (cbOutSize <= 2) - -1 will be returned and last error not set
possible solution - at first - never use ansi version - GetRawInputDeviceInfoA
use this wrapper function.
ULONG GetRawInputDeviceInfoExW(_In_opt_ HANDLE hDevice,
_In_ UINT uiCommand,
_Inout_updates_bytes_to_opt_(*pcbSize, *pcbSize) LPVOID pData,
_Inout_ PUINT pcbSize)
{
switch (int i = GetRawInputDeviceInfoW(hDevice, uiCommand, pData, pcbSize))
{
case 0:
return ERROR_INSUFFICIENT_BUFFER;
case 1:
return ERROR_INVALID_NAME;
default:
if (0 > i)
{
return GetLastError();
}
*pcbSize = i;
return NOERROR;
}
}
example of usage: (/RTCs must be disabled )
void Demo()
{
PRAWINPUTDEVICELIST pRawInputDeviceList = 0;
UINT uiNumDevices = 0;
UINT cch, cchAllocated = 0;
union {
PVOID buf;
PWSTR name;
};
buf = 0;
while (0 <= (int)GetRawInputDeviceList(pRawInputDeviceList, &uiNumDevices, sizeof(RAWINPUTDEVICELIST)))
{
if (pRawInputDeviceList)
{
do
{
HANDLE hDevice = pRawInputDeviceList->hDevice;
ULONG dwError;
while (ERROR_INSUFFICIENT_BUFFER == (dwError =
GetRawInputDeviceInfoExW(hDevice, RIDI_DEVICENAME, name, &(cch = cchAllocated))))
{
if (cch > cchAllocated)
{
cchAllocated = RtlPointerToOffset(buf = alloca((cch - cchAllocated) * sizeof(WCHAR)),
pRawInputDeviceList) / sizeof(WCHAR);
}
else
{
__debugbreak();
}
}
if (dwError == NOERROR)
{
DbgPrint("[%p, %x %S]\n", hDevice, pRawInputDeviceList->dwType, name);
}
else
{
DbgPrint("error = %u\n", dwError);
}
} while (pRawInputDeviceList++, --uiNumDevices);
break;
}
pRawInputDeviceList = (PRAWINPUTDEVICELIST)alloca(uiNumDevices * sizeof(RAWINPUTDEVICELIST));
}
}
This code is working fine on my PC. Not sure, but it indeed could be RDP issue.
UINT result = ::GetRawInputDeviceInfoW(m_Handle, RIDI_DEVICENAME, nullptr, &size);
if (result == static_cast<UINT>(-1))
{
//PLOG(ERROR) << "GetRawInputDeviceInfo() failed";
return false;
}
DCHECK_EQ(0u, result);
std::wstring buffer(size, 0);
result = ::GetRawInputDeviceInfoW(m_Handle, RIDI_DEVICENAME, buffer.data(), &size);
if (result == static_cast<UINT>(-1))
{
//PLOG(ERROR) << "GetRawInputDeviceInfo() failed";
return false;
}
DCHECK_EQ(size, result);
In the following code there is already check for nullptr in (1):
int msg;
struct x * var[2];
if ((var[0] = get_x()) == nullptr) { // (1)
return;
}
if (var[0]->data != 11) { // (2) <<< V595
msg = 1;
printf("msg1");
}
if (var[0] && var[0]->data == 12) { // (3) <<< V595
msg = 2;
return;
}
but I still get error: V595. Why?
I agree that there is an exceeding check for nullptr in (3).
Analyzer considers this piece of code abnormal. First, the pointer is being deferenced, and after that it is being verified. Even if it cannot be equal to NULL, it looks very suspicious. There's a possibility that wrong variable is used or checked.
So it is possible that the wrong variable is used, and the corrected version of code could look like:
if (FOO->data != 11) {
msg = 1;
printf("msg1");
}
if (var[0] && var[0]->data == 12) {
msg = 2;
return;
}
Or, probably, the condition is incorrect:
if (var[0]->data != 11) {
msg = 1;
printf("msg1");
}
if (FOO && var[0]->data == 12) {
msg = 2;
return;
}
Anyway, the analyzer doesn't like it, and it issues a warning. To eliminate such warnings, remove unnecessary checks which overload the code and confuse other programmers and the analyzer. In this case the analyzer will not issue the warning:
if ((var[0] = get_x()) == nullptr) {
return;
}
if (var[0]->data != 11) {
msg = 1;
printf("msg1");
}
if (var[0]->data == 12) {
msg = 2;
return;
}
If you don't want to remove this check, use one of the following ways to suppress warnings:
Suppression of false alarms
Mass Suppression of Analyzer Messages
I'm actually doing my own shell.
I have done the following special characters:
int commande(int fin, int fout, char * com, char * param, int * bg){
// execute a command
(ex. ls –l)
int symbole;
char *mot;
pid_t pid;
symbole = parsing();
switch(symbole){
case 0: // NL
case 1: // ;
case 2: // &
case 3: // <
case 4: // >
case 5: // | (Here I have some issues when I try to redirect the output of a command).
(correspond à ctrl+D)
case 10:// Mot
default:
}
return;
}
But I have some issues to do the redirection of an output when it is piped " |", when I have two instructions that follow themselves. Indeed I have tried the following operations which have all worked:
>myShell ps > fich
>myShell ls -l | wc -l
But not this one:
>myShell ls -l | wc -l >file
here are the two cases specifically developped. I think that the issue is in the case 5 and not in the case 4 because the first command I tried worked (which I shew you above).
case 4: // SYMBOLE : >
if(output==0){
output=1;
execute=1;
for (l=0;l<10;l++){
eltsoutput[l]=eltsCommande[l];
}
}
break;
case 5: // SYMBOLE : |
//if(tube==0){
/*for (l=0;l<10;l++){
eltstube[l]=eltsCommande[l];
}*/
p2=fork();
if(p2==0){
if(tube==0){
freopen( "fichtmp", "w", stdout );
execvp(eltsCommande[0], eltsCommande);
}
return(0);
}
else{ if(background==0){ // SANS MOD BG ATTENDRE FIN FILS
waitpid(p2, NULL, 0);
}
tube=1;
execute=1;
}
break;
Can you help me finding a way to execute two commands at the same time with | and that allow their result to go to a file?
In my shell, the case one work in the case of a redirection with an instruction ";":
}else if(output==1){
close(1);
int filew = creat(eltsCommande[0], 0644);
execvp(eltsoutput[0], eltsoutput);
Maybe I should use this code to make it work?
Looking at the NetBSD /bin/sh source code, I see the following pipe implementation:
static int
sh_pipe(int fds[2])
{
int nfd;
if (pipe(fds))
return -1;
if (fds[0] < 3) {
nfd = fcntl(fds[0], F_DUPFD, 3);
if (nfd != -1) {
close(fds[0]);
fds[0] = nfd;
}
}
if (fds[1] < 3) {
nfd = fcntl(fds[1], F_DUPFD, 3);
if (nfd != -1) {
close(fds[1]);
fds[1] = nfd;
}
}
return 0;
}
This function is called by evalpipe with 2 file descriptors:
STATIC void
evalpipe(union node *n)
{
struct job *jp;
struct nodelist *lp;
int pipelen;
int prevfd;
int pip[2];
TRACE(("evalpipe(0x%lx) called\n", (long)n));
pipelen = 0;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next)
pipelen++;
INTOFF;
jp = makejob(n, pipelen);
prevfd = -1;
for (lp = n->npipe.cmdlist ; lp ; lp = lp->next) {
prehash(lp->n);
pip[1] = -1;
if (lp->next) {
if (sh_pipe(pip) < 0) {
if (prevfd >= 0)
close(prevfd);
error("Pipe call failed");
}
}
if (forkshell(jp, lp->n, n->npipe.backgnd ? FORK_BG : FORK_FG) == 0) {
INTON;
if (prevfd > 0) {
close(0);
copyfd(prevfd, 0, 1);
close(prevfd);
}
if (pip[1] >= 0) {
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1, 1);
close(pip[1]);
}
}
evaltree(lp->n, EV_EXIT);
}
if (prevfd >= 0)
close(prevfd);
prevfd = pip[0];
close(pip[1]);
}
if (n->npipe.backgnd == 0) {
exitstatus = waitforjob(jp);
TRACE(("evalpipe: job done exit status %d\n", exitstatus));
}
INTON;
}
evalpipe is called in a switch statement in evaltree as follows:
case NPIPE:
evalpipe(n);
do_etest = !(flags & EV_TESTED);
break;
... which is called by the infinite loop in evalloop, and percolates up the tree till it gets to the eval function. I hope this helps.
I have a program that reads from a .txt file
I use the cmd prompt to execute the program with the name of the text file to read from.
ex: program.exe myfile.txt
The problem is that sometimes it works, sometimes it doesn't.
The original file is 130KB and doesn't work.
If I copy/paste the contents, the file is 65KB and works.
If I copy/paste the file and rename it, it's 130KB and doesn't work.
Any ideas?
After more testing it shows that this is what makes it not work:
int main(int argc, char *argv[])
{
char *infile1
char tmp[1024] = { 0x0 };
FILE *in;
for (i = 1; i < argc; i++) /* Skip argv[0] (program name). */
{
if (strcmp(argv[i], "-sec") == 0) /* Process optional arguments. */
{
opt = 1; /* This is used as a boolean value. */
/*
* The last argument is argv[argc-1]. Make sure there are
* enough arguments.
*/
if (i + 1 <= argc - 1) /* There are enough arguments in argv. */
{
/*
* Increment 'i' twice so that you don't check these
* arguments the next time through the loop.
*/
i++;
optarg1 = atoi(argv[i]); /* Convert string to int. */
}
}
else /* not -sec */
{
if (infile1 == NULL) {
infile1 = argv[i];
}
else {
if (outfile == NULL) {
outfile = argv[i];
}
}
}
}
in = fopen(infile1, "r");
if (in == NULL)
{
fprintf(stderr, "Unable to open file %s: %s\n", infile1, strerror(errno));
exit(1);
}
while (fgets(tmp, sizeof(tmp), in) != 0)
{
fprintf(stderr, "string is %s.", tmp);
//Rest of code
}
}
Whether it works or not, the code inside the while loop gets executed.
When it works tmp actually has a value.
When it doesn't work tmp has no value.
EDIT:
Thanks to sneftel, we know what the problem is,
For me to use fgetws() instead of fgets(), I need tmp to be a wchar_t* instead of a char*.
Type casting seems to not work.
I tried changing the declaration of tmp to
wchar_t tmp[1024] = { 0x0 };
but I realized that tmp is a parameter in strtok() used elsewhere in my code.
I here is what I tried in that function:
//tmp is passed as the first parameter in parse()
void parse(wchar_t *record, char *delim, char arr[][MAXFLDSIZE], int *fldcnt)
{
if (*record != NULL)
{
char*p = strtok((char*)record, delim);
int fld = 0;
while (p) {
strcpy(arr[fld], p);
fld++;
p = strtok('\0', delim);
}
*fldcnt = fld;
}
else
{
fprintf(stderr, "string is null");
}
}
But typecasting to char* in strtok doesn't work either.
Now I'm looking for a way to just convert the file from UTF-16 to UTF-8 so tmp can be of type char*
I found this which looks like it can be useful but in the example it uses input from the user as UTF-16, how can that input be taken from the file instead?
http://www.cplusplus.com/reference/locale/codecvt/out/
It sounds an awful lot like the original file is UTF-16 encoded. When you copy/paste it in your text editor, you then save the result out as a new (default encoding) (ASCII or UTF-8) text file. Since a single character takes 2 bytes in a UTF-16-encode file but only 1 byte in a UTF-8-encoded file, that results in the file size being roughly halved when you save it out.
UTF-16 is fine, but you'll need to use Unicode-aware functions (that is, not fgets) to work with it. If you don't want to deal with all that Unicode jazz right now, and you don't actually have any non-ASCII characters to deal with in the file, just do the manual conversion (either with your copy/paste or with a command-line utility) before running your program.
I am working on a simple application that takes the output from another one and writes it to a socket.
Below is the code for the application that I am execvp'ing
this code is called simple App
int main( int argc, char * argv[])
{
int count = 0;
while(count < 5)
//Attempt fork
if((pid2 = fork()) < 0) //Failed to fork
{
printf("\n Failed to fork in Dump \n");
exit(1);
}
else if (pid2 == 0) //Child Code
{
dup2(STDOUT_FILENO,pipefd[1]);
close(pipefd[0]);
close(STDOUT_FILENO);
if(execvp("../App/App", dumpParam) < 0) //execute the app; returns -1 if failed
{
printf("\nFailed to execute App\n");
exit(1);
}
}
else //Parent
{
close(pipefd[1]);
memset(buff,'0',sizeof(buff));
printf("here\n");
while( (r = read(pipefd[0],buff,sizeof(buff))) >= 0)
{
printf("\nSuccess in read r = %d\n",r);
printf("\nBuff = %s\n",buff);
memset(buff,'0',sizeof(buff));
}
printf("nowHere\n");
}
return pipefd[0];
so far when i run it, it prints out just a ton of 0's. if i set read > 0 then it doesn't run at all. Thoughts?
The read is returning 0 (end of file) because the child end of the pipe is closed.
You've got the dup2 the wrong way round, it should be
dup2(pipefd[1],STDOUT_FILENO)
also remove
close(STDOUT_FILENO)