为什么fscanf不扫描行尾的整数？

Question

I'm trying to read in a file that contains multiple lines of the form:

www.someurl.com,timestamp

I am using the following code:

char url[256];
unsigned int timestamp;

// Read each line from the input file.
while(fscanf(inputfile, "%s,%d", url, &timestamp) == 2) {
    printf("%s was visited at %d\n", url, timestamp);
}

However, fscanf scans the entire line into the string, and does not scan the timestamp into the integer. I'm sure this is a very basic mistake, but I can't figure it out. Could someone please explain why this is, and how I can go about fixing it?

Answer 1

When processing %s , fscanf expects a whitespace terminated string, and it's greedy as well. So the entire line is read into the url.

You can specify the forbidden character set directly:

fscanf(inputfile, "%[^,],%d", url, &timestamp)

Here's a bit more data about fscanf variants and the format string.