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Old 05-10-2003, 10:24 PM   #1
Zed
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Pass text to variable


Im having trouble executing a system command and having it pass the text to a variable, anyone have any idea how to do it?

Whenever i try i get "Invalid Initializer"

help would be appreciated - thanks

edit:
Something like
system("uname -r") /*returns the hostname*/
and setting a variable as that instead of having to call system("uname -r") every time.

Last edited by Zed; 05-10-2003 at 10:26 PM.
 
Old 05-11-2003, 12:34 AM   #2
td3201
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I am assuming this is perl....which isnt stated anywhere:

chomp( $hostname = `uname -r` );
print "$hostname\n";
 
Old 05-11-2003, 05:55 AM   #3
Zed
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sorry about that, i meant C

Ive been a little absent minded lately

Last edited by Zed; 05-11-2003 at 06:00 AM.
 
Old 05-11-2003, 11:01 AM   #4
td3201
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Well, you did use a c-style comments....
 
Old 05-11-2003, 02:05 PM   #5
Zed
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Any idea? I mean ive tried something like

char blah = system("uname -n");

but like, its not setting blah as the command, instead it executes "uname -n" as a seperate process, then when you call blah, it equals 0.

Example:
Code:
#include <stdio.h>

#include <string.h>

void sysinfo();



int main()

{
sysinfo();
return(0);

}

void sysinfo()
{
char host = system("uname -n");
printf("blah blah blah %d", host);
}
It returns this:
localhost.localdomain
blah blah blah 0

and not:
blah blah blah localhost.localdomain


any Ideas?

Last edited by Zed; 05-11-2003 at 02:09 PM.
 
Old 05-12-2003, 03:48 PM   #6
cYbORg
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Well - of course it happens like that, cause system() returns zero on success and thatfore you receive the zero-character '\0' into your host-variable. If (what is definately not the case) uname returned the host, the returnvalue would be c-string (a pointer to the first char of the string) and therefore you'd have needed a char*. Actually, uname prints any output to STDOUT which here is the console.
You can force the output to be written in a textfile and then read it's content into the variable. Here is an yet untested example:
Code:
#include <stdio.h>
#ifndef MAX_PATH
#define MAX_PATH 256
#endif

void sysinfo(){
	if(system("uname -r >/tmp/MyTempHostFile") == 0){
		FILE *HostFile;
		if(!(HostFile = fopen("/tmp/MyTempHostFile", "r")))
			return;
		else{
			char szHostName[MAX_PATH];
			int nBytesRead = fread(szHostName, MAX_PATH, 1, HostFile);
			// Don't forget the null-termination!
			szHostName[nBytesRead] = '\0';
			fclose(HostFile);
			printf("blah blah blah %s", szHostName);
		}
	}
}
Hope that might help you out so far.

Greetz, Gary
 
Old 05-12-2003, 04:02 PM   #7
cYbORg
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Well, another way would be, you use socket functions to return your hostname without that file-stuff. How about that (it's also untested:
Code:
#ifndef MAX_PATH
#define MAX_PATH 256
#endif

void getsysinfo(const char *szHostName);

int main(){
	char host[MAX_PATH];
	getsysinfo(host);
	printf("blah blah blah %s", host);
	return 0;
}

void getsysinfo(const char *szHostName){
	if(!szHostName)
		return;
	else{
		char *szIP = "127.0.0.1";
		struct HOSTENT *pHostName = gethostbyaddr(szIP, sizeof szIP, AF_INET);
		strcpy(szHostName, pHostName->h_name);
	}
}
Think, that might be more useful. And: it's portable
Sorry about not including the headers, but I do not exactly know which ones to include. But there are sources...

So far, Gary
 
  


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