Libusb and how to its package

[sh4rif]

Hello everyone

I have a very important question...
I have installed libusb by using the following command i am not sure if it was right or not and the command was

sudo apt-get install libusb-dev

once I have installed (and I am not sure if it has installed or not), I want to know how would I use the library because I write some sample code which uses <libusb.h > but when i compile that c++ file using "g++ test_libusb.cpp" that throws the following error,

"test_libusb.cpp:2:20: fatal error: libusb.h: No such file or directory
compilation terminated."

I am clueless what to do cant find any source on the internet to get to the bottom of this... can anyone please help I am a desperate.. and please treat me as novice on both c/c++ and Ubuntu...

thanks a lot for you time folks

hoping for an early response...

thanks one more time
Sharif

[sh4rif]

code for my cpp file is below


#include <iostream>
#include <libusb.h>

using namespace std;

int main(){
//pointer to pointer of device used to retrieve a list of devices
libusb_device **devs;
libusb_device_handle *dev_handle; //a device handle
libusb_context *ctx = NULL; //A LIBUSB session
int r;// for return values
ssize_t cnt; //holding number of devices in list
r = libusb_init(&ctx); // initialize the library for the session we just declared

if(r < 0){
cout <<"init error "<<r<< endl;
return 1;
}

libusb_set_debug(ctx, 3); // set verbosity level to 3, as suggested in the documentation
cnt = libusb_get_device_list(ctx, &devs); //get the list of devices

if (cnt < 0) {
cout <<"Get Device Error "<< endl; // there was an error
return 1;
}

cout <<cnt<<" Device in list "<< endl;
dev_handle = libusb_open_device_with_vid_pid(ctx, 5118, 7424) // these are vendor id and product id

if (dev_handle == null){
cout<<"Cannot open device "<<endl;
}else{
cout<<"Device opened"<<endl;
}

libusb_free_device_list(devs, 1);// free the list unref the devices in it

unsigned char *data = new unsigned char[4];//data to write
data[0] = 'a';data[1] = 'b';data[2] = 'c';data[3] = 'd';//some dummy values

int actual; //used to find how many bytes were written

if (libusb_kernal_driver_active(dev_handle, 0) == 1){// findout if kernal driver attached
cout<<"Kernal Driver Active"<<endl;
if(libus_detach_kernal_driver(dev_handle, 0) == 0 ){ //detach it
cout<<"Kernal Driver Detached"<<endl;
}
}

r = libusb_claim_interface(dev_handle, 0);// claim interface 0 (the first) of devices

if(r < 0){
cout <<"Cannot claim interface "<<endl;
return 1;
}

cout <<"Claimed interface "<<endl;

cout<<"data->"<<data<<"<-"<<endl; // just to see the data we want to write : abcd
cout<<"Writing data..."<<endl;

r = libusb_bulk_transfer(dev_handle, (2 | LIBUSB_ENDPOINT_OUT), data, 4, &actual, 0);//my device's out endpoint was 2, found withe trial - the device had two endpoints: 2 and 129

if(r == 0 && actual == 4){ // we wrote 4 bytes successfully
cout<<"Writing successfull"<<endl;
}else{
cout<<"write error"<<endl;
}

r = libusb_release_interface(dev_handle, 0); // release the claimed interface

if (r != 0){
cout<<"Cannot release interface"<<endl;
retrun 1;
}
cout<<"Released interface"<<endl;
libusb_close(dev_handle); // close the device we opened
libusb_exit(ctx); // need to be called to end the

delete[] data// delete the allocated memory for data
return 0;
//printf("Hello libusb!");
//return 0;
}

[steeldriver]

I think the header file supplied by that package is called usb.h (not libusb.h) - try changing your include instruction to


#include <usb.h>

[sh4rif]

this does not work coz if you check other examples (btw i have copied this example from a website) they are all using libusb

[steeldriver]

Well that file is not part of the libusb-dev package (at least, not on 12.04)


$ apt-file show libusb-dev | grep '\.h$'
libusb-dev: /usr/include/usb.h
It seems to be in libusb-1.0-0-dev


$ apt-file search -x 'libusb\.h$'
apcupsd-doc: /usr/share/doc/apcupsd/examples/libusb.h
libusb-1.0-0-dev: /usr/include/libusb-1.0/libusb.h
Note that because it's in a subdir of /usr/include you would need to specify it as


#include <libusb-1.0/libusb.h>or add a -I include path

If you want to search on your own system, you can use the apt-cache tool and/ or install apt-file - it's very useful for tracking down this kind of thing

[sh4rif]

thank you very much "steeldriver (http://ubuntuforums.org/member.php?u=1627500)" that explanation clears some confusion in my mind but...thanks once again for that

btw which one is the latest and which one should i use?
libusb-dev or libusb-1.0-0-dev (considering I am a layman in c/c++ and libusb)
any resources to learn or understand libusb just wanna run a simple code...

thanks once again you are a STAR 10 out of 10 for your effort