LinuxQuestions.org - scanf doesn't interrupt flow to read input

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scanf doesn't interrupt flow to read input

hello.
The idea behind my program is to get some numbers to send it asynchronously to a process. The decimals are red from the keyboard.

Code:

#include <stdio.h>



int main(void)

{

        printf("We need integer values. Could you provide us some, please?\n");

        printf("Press Ctrl-C when you have no more to give\n");

        while(1)

        {

                int temp;

                printf("Number? :");

                int ret = scanf("%d", &temp);

                // ferror associated to stdin is 0 at this point  

                if (!ret)

                {

                        printf("This might not be a number.\n");

                        printf("Please try again. What about right now?\n");

                        continue;

                }

                else

                {

                        // Good data. Can send them as useful

                }

        }

}

So, if the user sends an "it", the input shall be ignored, and user prompted for another number. At least that's what I expect. The fact is once an errouneous input is provided, the program behaves as the line containing the call to scanf didn't exist.
I tried to read ferror(stdin). It is 0 in any case.

Any hints will be endlessly appreciated.

Linux 2.6.14.2 PREEMPT i686 GNU/Linux
gcc (GCC) 3.3.6 (Debian 1:3.3.6-13)

That's how scanf() works. In your case, you should read a line as string (using getchar, fgets or read), then use atoi to convert it to a number and that, looking at the result, print the message or deal with the number you have.

scanf is a function I try to steer clear of.

Quote:

then use atoi to convert it to a number

Better to use strtol, since atoi doesn't detect errors.

Thank you for your help. I'll look with another pair of eyes at the scanf family.

Regards.