popen help

[ojschubert]

Hello,
I'm trying to open a Linux shell script which searches a document for a particular number.

I would like to get this number into a variable for use in my C-program so I can test it.

I use popen and the correct number is displayed by my C program, but I cannot seem to do anything with it. For instance I am unable to get the correct value into another function.

What's going on here? Thanks for any help

OJ

int main ( )
{
    while (1){
    char buff[BUFSIZ];
    FILE *fp = popen( ". getfile", "r" );            
    while ( fgets( buff, BUFSIZ, fp ) != NULL ) {
        }
        pclose( fp );
    printf("variable buff is: %s\n",buff); 
                   //This displays "10" which is correct

      use_info (*buff);
    }
    return 0;
}

int use_info (int var)    {
    printf("Values passed to function is %d\n", var);
                    //This displays "49" which is incorrect
}

[DavT]

Its quite hard from your code to work out what you are trying to acheive, but I think your problem is in the value that you pass to use_info(). You are passing the first character in the string 'buff' as a parameter. The first character you tell us is '1' so this gets converted to an integer (in ascii, '1' == 49) and the value gets printed to the screen. If you want to print out the value stored in the string then you will have to use a conversion function such as atoi(). eg:

  ...
  printf ("variable buff is: %s\n", buff);
  use_info (atoi(buff));
  ...

int use_info (int var) 
{
  printf ("value passed to function is %d\n", var);
}

[ojschubert]

Thanks dav,
That did it,

OJ