here is my code concerning libsensors.
libraries:
#include <unistd.h>
#include <sensors/sensors.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
code concerning libsensors:
char sd[16384]="^\0",bf[1];
char buf2[8192]="^\0";
sensors_chip_name const* scn;
int c=0;
int t4=1;
while((scn=sensors_get_detected_chips(0,&c))!=0)
{
sensors_feature const *fea;
int f=0;
strcat(sd,scn->prefix);
printf("%s",scn->prefix);
strcat(sd,":");
strcat(sd,scn->path);
strcat(sd,"(");
while((fea=sensors_get_features(scn,&f))!=0)
{
strcat(sd,fea->name);
strcat(sd,"(");
sensors_subfeature const *sb;
int s=0;
while((sb=sensors_get_all_subfeatures(scn,fea,&s))!=0)
{
t4++;
strcat(sd,sb->name);
strcat(sd,",");
int t3=-1;
int i=0;
char t8[sizeof(sb->number)];
memcpy(&t8,&(sb->number),sizeof(sb->number));
strcat(sd,t8);
strcat(sd,"!");
}
strcat(sd,")");
}
strcat(sd,")");
}
so when I try to print anything nothing happens. char array called sd returns empty. it simply seems that there are no sensors to be read.
when I run sensors from terminal it works perfectly fine. I see a couple of cores and chips temps.
I implemented this code from some post on here and to be frank I don't totally understand it.
Posting #user3629249 comment as a community answer.
It it required to first call sensors_init() otherwise the chips list will be empty.
This function expects a sensors configuration file as argument, or NULL to use the default one.
Also, you can find an usage example in this related question: Has anyone been able to use libsensors properly?
Related
I am checking socket options and I got this error when I compile. I tried to google it and it looks like no one has encountered this problem before.
#include <netinet/tcp.h>
#include <stdio.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdlib.h>
static char *sock_str_flag(union val *, int);
struct sock_opts {
const char *opt_str;
int opt_level;
int opt_name;
char *(*opt_val_str)(union val *, int);
}sock_opts[] = {
{ "SO_USELOOPBACK", SOL_SOCKET, SO_USELOOPBACK, sock_str_flag } //this is the error
};
The socket option SO_USELOOPBACK is not a POSIX standard. The man page setsockopt() describes the nature of SO_USELOOPBACK in detail.
The SO_USELOOPBACK is a [Digital] standard. Text paragraphs preceded by [Digital] document features that are included in the DIGITAL UNIX software but are not currently specified by any standard that applies to the interface being described. Use these features when source code portability across multiple UNIX platforms is less important than the capabilities that the features provide.
For portability, you need to have ifdef checks.
struct sock_opts {
const char *opt_str;
int opt_level;
int opt_name;
char *(*opt_val_str)(union val *, int);
}sock_opts[] = {
/* .... */
#ifdef SO_USELOOPBACK
{"SO_USELOOPBACK", SOL_SOCKET, SO_USELOOPBACK, sock_str_flag }
#endif
/* .... */
};
i'm facing a problem in C where i'm trying to use some getter and setter to share a variable between multiple source file.
I declare here my variable (ok_button) with a getter and a setter:
variable.c
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include "../libhd_src/libhd.h"
int ok_button;
void set_ok_button(int value){
ok_button=value;
printf("Setting ok");
}
int get_ok_button(){
return ok_button;
}
Here, when i push a button, it sets the variable to 1. (Can't upload the full code of this source file, but i see in my logs that the function set_ok_button is correctly execuded when i press (i see the printf "Setting OK" everytime i press my button))
button.c
#include "../libhd_src/libhd.h"
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
void * button_back_center_short(void *arg){
set_ok_button(1);
return 0;
}
And here, i simply check the value of my variable with the getter function.
read.c
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include "../../libhd_src/libhd.h"
int main(int argc, char **argv){
while(1){
printf("Value %d", get_ok_button());
usleep(500000);
}
}
The problem is that the value shown in read.c is always "0" even when i press my button and set the value to 1...
Does someone understand what's wrong ? Feel free to tell me if you see a better solution to do that :)
I think your problem may be that you have multiple set_ok_button and get_ok_button functions in different files. Make sure you only have them defined in one file, and in a header add 2 lines declaring (but not defining) the functions:
void set_ok_button(int value);
int get_ok_button();
I'm trying to understand how the I/O between processes mechanism works.
I have tried to run this code:
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
...
char *const paramList[] = {"/bin/cat"};
close(0);
open("./my_file", O_RDONLY);
execv("/bin/cat",paramList);
...
but got nothing going on. (it compiles, though)
what did I do wrong and what does my code do?
Per the docs for execv:
The array of pointers must be terminated by a NULL pointer.
Thus, add NULL to the end of paramList.
If you're still having trouble, make sure to check the return values from all syscalls, and see if any of your calls are failing.
I have to get name server IP of my system using C language.I am using Linux machine.
I have tried.
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/cdefs.h>
int main()
{
int res_init(void);
printf("_res.nscount %d\n",_res.nscount);
//printf("_res.nsaddr_list[0] %s\n",_res.nsaddr_list[0]);
return 0;
}
But I am getting _res.nscount as 0.Am I doing anything wrong?
You declared res_init() instead of calling it. Try:
Int main()
{
res_init();
/* ... */
However, nsaddr_list[0] isn't a string, so you won't be able to print it with printf("%s"). You'll have to use inet_ntoa() or similar to convert its sin_addr.s_addr value to a printable string.
I have a piece of code that used to work in some environment a long time ago. I'm pretty sure it was a FreeBSD machine so I got FreeBSD 8.3 and I'm trying to make this file but it's not working.
When I try to compile it it complains with:
f.c: In function 'tcp'>
f.c:24: error: storage size of 'socket_stru' isn't known
f.c:29: error: 'IPPROTO_TCP' undeclared (first use in this function)
...
I've been looking around and I see these are all specified in the sys/socket.h file. This is my actual file:
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/socket.h>
#include <unistd.h>
#include "f.h"
int tcp4 (in_addr_t ip, int port, int qsize )
{
struct sockaddr_in socket_stru; // line 24
socket_stru.sin_family = AF_INET;
socket_stru.sin_port = htons(port);
socket_stru.sin_addr.s_addr = ip;
int actual_socket = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP); // line 29
...
I feel like my code somehow doesn't "read" the sys/socket.h file so it doesn't know about socket_stru and IPPROTO_TCP, but I'm just really lost.
Any ideas?
None of the other answers worked for me. After taking a look inside the sys/socket.h file, I didn't even see a definition for struct sockaddr_in.
What worked for me was to #include one of the following files when using the corresponding struct sockaddr_* type:
if you're using struct sockaddr_in, #include <netinet/in.h>
if you're using struct sockaddr_un, #include <sys/un.h>
if you're using struct sockaddr_ns, #include <netns/ns.h>
if you're using struct sockaddr_ndd, #include <sys/ndd_var.h>
More information on the header files for socket programming can be found here.
I cut and paste your code into a file (removing only the #include f.h and closed off the function call.) It compiles just fine on Linux.
I suspect there may be header files differences on BSD. For socket programming, I typically include ALL these header files. And I know my socket code compiles on BSD as well. I suspect one of these header files brings in the definition for sockaddr_in. I recall when I ported by socket code to BSD, I had to explicitly add a few of these.
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <stdlib.h>
#include <memory.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <stdarg.h>
/* the next two includes probably aren't relevant for you, but I typically use them all anyway */
#include <math.h>
#include <sys/termios.h>
Hope this helps
I had the same problem, but the following include fixed the issue for me
#include <arpa/inet.h>
Just add #include <resolv.h> to your source and you are good to go.
According to freebsd developer's handbook you need
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>