I'm new to Gtkmm and trying to load a txt-file into a Text-Buffer. When I start my program I get a output like this: Output
My code for filling the Text-Buffers looks like this:
void ExampleGui::fill_buffers()
{
FILE *fp = fopen("/home/User/Documents/Gui/test1.txt", "r");
if (fp == NULL)
exit(EXIT_FAILURE);
char *line = NULL;
size_t len = 0;
char *output = NULL;
while ((getline(&line, &len, fp)) != -1) {
output = line;
}
fclose(fp);
if (line)
free(line);
m_refTextBuffer1 = Gtk::TextBuffer::create();
m_refTextBuffer1->set_text("Welcome!\nClick the button Show Text to start.");
m_refTextBuffer2 = Gtk::TextBuffer::create();
m_refTextBuffer2->set_text(Glib::convert_with_fallback(output, "UTF-8", "ISO-8859-1"));
}
How can I fix that wrong output and why do I get it?
The main problem here is the assignment output = line followed by free(line).
Because output points to the same memory as line that means output becomes invalid.
Either don't free the memory until you're done with the string, or duplicate the string in line (which the assignment doesn't do).
Related
dcmtk3.6.3
I used C++ to code the function of popen("findscu -v", "r").
I want to get the output message of findscu to save in file.
But it only print to the console, i cannot save to file.
//--verbose verbose mode, print processing details
FILE * fstream = popen("findscu --verbose", "r");
The output message of findscu is print to console.
char * p = fgets(buff, sizeof(buff), fstream);
p is NULL, and the buff is nothing.
But if i use this code:
//--help print this help text and exit
FILE * fstream = popen("findscu --help", "r");
It does not print to the console.
char * p = fgets(buff, sizeof(buff), fstream);
p is not NULL, and the buff has the output message.
That is what I want.
What is the differents of this two cases?
How to get the message from case 1?
thanks.
ubuntu18.04
C++
dcmtk3.6.3
findscu
//C++ dcmtk findscu
FILE * fstream = popen("findscu --verbose", "r");
char buff[10240] = {0};
char * p = fgets(buff, sizeof(buff), fstream);
cout << buff << endl;
I expect get output info from the buff, not from the console.
Case 2 is what i want.
Case 1 is what i dont want.
First off, I do mostly C#, .Net development so go easy on me if this is a stupid question.
I am implementing an Ericcson open source project to convert an image to another format. The problem is that on conversion an output to a console happens as follows...
1 file(s) copied.
I need to suppress this dialog that pops up. I just want to execute the system command with no output. I think I have isolated the area of the code causing this.
void writeOutputFile(char *dstfile, uint8* img, uint8* alphaimg, int width, int height)
{
char str[300];
if(format!=ETC2PACKAGE_R_NO_MIPMAPS&&format!=ETC2PACKAGE_RG_NO_MIPMAPS)
{
fWritePPM("tmp.ppm",width,height,img,8,false);
//PRINTF("Saved file tmp.ppm \n\n");
}
else if(format==ETC2PACKAGE_RG_NO_MIPMAPS)
{
fWritePPM("tmp.ppm",width,height,img,16,false);
}
if(format==ETC2PACKAGE_RGBA_NO_MIPMAPS||format==ETC2PACKAGE_RGBA1_NO_MIPMAPS||format==ETC2PACKAGE_sRGBA_NO_MIPMAPS||format==ETC2PACKAGE_sRGBA1_NO_MIPMAPS)
fWritePGM("alphaout.pgm",width,height,alphaimg,false,8);
if(format==ETC2PACKAGE_R_NO_MIPMAPS)
fWritePGM("alphaout.pgm",width,height,alphaimg,false,16);
// Delete destination file if it exists
if(fileExist(dstfile))
{
sprintf(str, "del %s\n",dstfile);
system(str);
}
int q = find_pos_of_extension(dstfile);
if(!strcmp(&dstfile[q],".ppm")&&format!=ETC2PACKAGE_R_NO_MIPMAPS)
{
// Already a .ppm file. Just rename.
sprintf(str,"move tmp.ppm %s\n",dstfile);
//PRINTF("Renaming destination file to %s\n",dstfile);
}
else
{
// Converting from .ppm to other file format
//
// Use your favorite command line image converter program,
// for instance Image Magick. Just make sure the syntax can
// be written as below:
//
// C:\imconv source.ppm dest.jpg
//
if(format==ETC2PACKAGE_RGBA_NO_MIPMAPS||format==ETC2PACKAGE_RGBA1_NO_MIPMAPS||format==ETC2PACKAGE_sRGBA_NO_MIPMAPS||format==ETC2PACKAGE_sRGBA1_NO_MIPMAPS)
{
// Somewhere after version 6.7.1-2 of ImageMagick the following command gives the wrong result due to a bug.
// sprintf(str,"composite -compose CopyOpacity alphaout.pgm tmp.ppm %s\n",dstfile);
// Instead we read the file and write a tga.
//PRINTF("Converting destination file from .ppm/.pgm to %s with alpha\n",dstfile);
int rw, rh;
unsigned char *pixelsRGB;
unsigned char *pixelsA;
fReadPPM("tmp.ppm", rw, rh, pixelsRGB, 8);
fReadPGM("alphaout.pgm", rw, rh, pixelsA, 8);
fWriteTGAfromRGBandA(dstfile, rw, rh, pixelsRGB, pixelsA, true);
free(pixelsRGB);
free(pixelsA);
sprintf(str,""); // Nothing to execute.
}
else if(format==ETC2PACKAGE_R_NO_MIPMAPS)
{
sprintf(str,"imconv alphaout.pgm %s\n",dstfile);
//PRINTF("Converting destination file from .pgm to %s\n",dstfile);
}
else
{
sprintf(str,"imconv tmp.ppm %s\n",dstfile);
//PRINTF("Converting destination file from .ppm to %s\n",dstfile);
}
}
// Execute system call
system(str);
free(img);
if(alphaimg!=NULL)
free(alphaimg);
}
I am lost at this point about how to suppress the console that pops up. As we iterate through images via a reference to the dll, many many console windows flash on the screen. Need to stop this from happening.
Help is greatly appreciated.
Try doing:
strcat( str, " > nul" ) // for Windows or
//strcat( str, " > /dev/null" ) // for Unix
system( str )
If it doesn't help then this may help:
#include <string>
#include <ShellAPI.h>
int system_no_output( std::string command )
{
command.insert( 0, "/C " );
SHELLEXECUTEINFOA ShExecInfo = {0};
ShExecInfo.cbSize = sizeof(SHELLEXECUTEINFO);
ShExecInfo.fMask = SEE_MASK_NOCLOSEPROCESS;
ShExecInfo.hwnd = NULL;
ShExecInfo.lpVerb = NULL;
ShExecInfo.lpFile = "cmd.exe";
ShExecInfo.lpParameters = command.c_str();
ShExecInfo.lpDirectory = NULL;
ShExecInfo.nShow = SW_HIDE;
ShExecInfo.hInstApp = NULL;
if( ShellExecuteExA( &ShExecInfo ) == FALSE )
return -1;
WaitForSingleObject( ShExecInfo.hProcess, INFINITE );
DWORD rv;
GetExitCodeProcess( ShExecInfo.hProcess, &rv );
CloseHandle( ShExecInfo.hProcess );
return rv;
}
and replace all your system() calls to system_no_output() ones.
To fully suppress the output, redirect both stdout and stderr:
system("command >nul 2>nul");
Take a look here if you're using C#. The class used in C# is ProcessStartInfo.
In the example in the link, look at the OpenWithStartInfo member function which will minimize the console.
As far as doing this in C++, take a look at the spawn family of functions here.
The block of code here runs fine till the _read function is called, after that it changes the value of file handle variable 'fh' for no reason.
std::string& xLogFile;
std::string& xBuffer;
struct _stat& xStatBuffer)
char *buffer;
buffer = (char *)malloc(sizeof(char) * xStatBuffer.st_size);
#define _O_RDONLY 0x0000 /* open for reading only */
int fh = 0, read_bytes =0;
fh = _open(xLogFile.c_str(), _O_RDONLY); // ToDo function deprecated should be changed to fstream
if (fh ==1)
{
if (mWriteLog) IntPkgUtil::TraceLog("Error!! Couldn't open the log file");
return true;
}
read_bytes = _read(fh,&buffer,xStatBuffer.st_size);
_close(fh);
if (read_bytes <= 0)
{
if (mWriteLog) IntPkgUtil::TraceLog("Error!! Couldn't read the log file");
return true;
}
buffer[read_bytes] = '\0';
xBuffer = buffer;
This is a block of code i am using to read from a file into a buffer, but it is failing at the _read function, where the value of file handle 'fh' changes after the call to the function.
Fix the code as below, buffer and not &buffer. You are overwriting the stack.
read_bytes = _read(fh,buffer,xStatBuffer.st_size);
I would like to render files in node.js from C++ addon.
I want to apply some file processing and render the output to the browser via node.js
Here is my C++ Code
std::ifstream in(filename, std::ios::binary);
in.seekg (0, in.end);
int length = in.tellg();
in.seekg (0, in.beg);
char * buffer = new char [length];
in.read (buffer,length);
in.close();
return buffer;
Following is the V8 code to add bindings for node.js, here buffer is the output from the above c++ code.
Local<Function> cb = Local<Function>::Cast(args[1]);
const unsigned argc = 1;
Local<Value> argv[argc] = {Local<Value>::New(String::New(buffer))};
cb->Call(Context::GetCurrent()->Global(), argc, argv);
This code works well for normal text files. I'm getting problem when reading text files which are having unicode characters.
For eg,
Original text file
test start
Billél
last
When receiving in node, I will get
test start
Bill�l
last
Similarly when reading a jpg, png files the output file is different than the original file.
Please help.
I was having problems with this as well. I found an implementation in the V8 examples from Google. The example I found that properly handles UTF8 encoded files is found here:
https://code.google.com/p/v8/source/browse/trunk/samples/shell.cc#218
I adapted the source to this:
const char* ReadFile(const char* fileName, int* fileSize)
{
// reference to c-string version of file
char *fileBuffer = 0;
// attempt to open the file
FILE* fd = fopen(fileName, "rb");
// clear file size
*fileSize = 0;
// file was valid
if(fd != 0)
{
// get size of file
fseek(fd, 0, SEEK_END);
*fileSize = ftell(fd);
rewind(fd);
// allocate file buffer for file contents
fileBuffer = (char*)malloc(*fileSize + 1);
fileBuffer[*fileSize] = 0;
// copy file contents
for (int charCount = 0; charCount < *fileSize;)
{
int charRead = static_cast<int>(fread(&fileBuffer[charCount], 1, *fileSize - charCount, fd));
charCount += charRead;
}
// close the file
fclose(fd);
}
return fileBuffer;
}
Also, make sure when you create a V8 string that you create a String::Utf8Value.
String::Utf8Value v8Utf8String(...);
Then to use the String::Utf8Value as a char* use the following function:
https://code.google.com/p/v8/source/browse/trunk/samples/shell.cc#91
I have embedded a custom stream in a dump (i.e. passed the UserStreamParam argument to MiniDumpWriteDump function). Now, I'm trying to extract the stream from a WinDbg extension. (Note that I have verified that I can retrieve the stream using the MiniDumpReadDumpStream function).
I'm using the IDebugAdvanced2::Request method with DEBUG_REQUEST_READ_USER_MINIDUMP_STREAM request. I am able to retrieve data from standard streams. For example, the following snippet will correctly retrieve the contents of the misc info stream.
DEBUG_READ_USER_MINIDUMP_STREAM rums = {};
rums.StreamType = MiscInfoStream;
rums.Buffer = &buf;
rums.BufferSize = sizeof buf;
hr = p->Request(DEBUG_REQUEST_READ_USER_MINIDUMP_STREAM,
&rums, sizeof rums, 0, 0, 0);
However, trying to retrieve my own stream will result in an error (0x80070570, ERROR_FILE_CORRUPT) and WinDbg outputs
Dir entry 11, ??? stream has unknown stream type 6381921
Note that the same message appears as a part of the .dumpdebug output.
Stream 11: type ??? (6381921), size 00000038, RVA 00033FA9
Dir entry 11, ??? stream has unknown stream type 6381921
What is the problem? How do I retrieve contents of my user stream?
very late answer
StreamType cannot be UserDefined StreamTypes
jen-lung chiu of ms posted so in osronline windbg lists long back
do not know if the latest dbgeng has this limitation eliminated
you either retrieve it with a dbghelp function independently
(using dbghelp functions inside windbg extensions are not recommended )
or parse the stream yourself with fopen() fread() like below
userstream:\>type ..\usrstr.cpp
#include <stdio.h>
#include <engextcpp.hpp>
#include <dbghelp.h>
const ULONG MBUFFSIZE = 0x1000;
PVOID Buff = 0;
int __cdecl ReadUserStream (char *dmpfile)
{
PMINIDUMP_HEADER MiniHeader = 0;
PMINIDUMP_DIRECTORY MiniDir = 0;
PMINIDUMP_USER_STREAM userstream = 0;
size_t result = 0;
ULONG Streams =0;
ULONG i = 0;
FILE * fp = fopen(dmpfile,"rb");
if (fp)
{
result = fread(Buff, 1, sizeof(MINIDUMP_HEADER), fp );
if ( result == sizeof(MINIDUMP_HEADER) )
{
MiniHeader = (PMINIDUMP_HEADER) Buff;
Streams = MiniHeader->NumberOfStreams;
for (i = 0; i < Streams; i++ )
{
result = fread( Buff, 1, sizeof(MINIDUMP_DIRECTORY), fp );
if ( result == sizeof(MINIDUMP_DIRECTORY) )
{
MiniDir = (PMINIDUMP_DIRECTORY) Buff;
if ( MiniDir->StreamType > LastReservedStream )
{
userstream = (PMINIDUMP_USER_STREAM)Buff;
ULONG savedbuffsize = userstream->BufferSize;
ULONG savedtype = userstream->Type;
PCHAR savedbufferptr = (PCHAR)userstream->Buffer;
long pos = ftell(fp);
fseek(fp, (long)savedbufferptr,SEEK_SET);
result = fread( Buff, 1, savedbuffsize, fp );
if ( result == savedbuffsize )
{
printf(
"\n"
"Datastream Type = %.8x\n"
"Buffer Size = %.8x\n"
"Buffer = %p\n"
"Buffer content = %s\n"
"\n",
savedtype,
savedbuffsize,
savedbufferptr,
Buff
);
fseek(fp,pos,SEEK_SET);
continue;
}
else
{
printf(
"failed to read buffer contents at offset %p of
user stream %x\n",
savedbufferptr,
savedtype);
fseek(fp,pos,SEEK_SET);
continue;
}
}
}
else
{
printf("failed to fread Minidump directory exiting \n");
goto getout;
}
}
}
else
{
printf("failed to fread Minidump header exiting \n");
goto getout;
}
}
else
{
printf("failed to open dmp file exiting \n");
goto getout;
}
getout:
if (fp)
fclose(fp);
return 0;
}
int __cdecl main (int argc, char * argv[])
{
if (argc !=2)
{
printf("Usage %s %s\n",argv[0],"somedump.dmp");
return 0;
}
Buff = malloc( MBUFFSIZE );
if (Buff)
{
ReadUserStream(argv[1]);
free(Buff);
return 0;
}
else
{
printf("malloc failed exiting\n");
return 0;
}
}
output from an userdump that has userStreams in it
(oleg staradumov debuginfo.com writeuserstream.cpp )
userstream:\>usrstr.exe
Usage usrstr.exe somedump.dmp
userstream:\>usrstr.exe test.dmp
Datastream Type = 00010000
Buffer Size = 00000021
Buffer = 000010B6
Buffer content = This is the first data stream...
Datastream Type = 00010001
Buffer Size = 00000023
Buffer = 000010D7
Buffer content = and this is the second data stream
I found this topic while looking for a method to read out user stream from the dbg file.
#blabb 's answer is correct in basics and helped me a lot, but it has a two flaws:
You should use the MINIDUMP_HEADER.StreamDirectoryRva to locate the MINIDUMP_DIRECTORY list.
You should not convert the MINIDUMP_DIRECTORY entry to MINIDUMP_USER_STREAM, because that's an error (MINIDUMP_USER_STREAM is a bigger struct than MINIDUMP_DIRECTORY, so you are reading uninitialized memory there) Use the MINIDUMP_DIRECTORY to locate the needed part of the stream.
Even if not tested, it should work if you fill StreamType with a custom value (greater than LastReservedStream = 0xFFFF) instead of MiscInfoStream.