Share this page

# fscanf

Input-Output Functions

Reads formatted input from a stream.

    int fscanf( FILE *file_pointer, const char *format string [, args]);

file_pointer | A pointer to a file.
string | One or more formatting characters.
args | One or more optional print arguments.

For fscanf details, refer to your C language documentation.

## Return Values

The number of items successfully read. This count does not include any ignored fields. If EOF is returned, an error has occurred before the first assignment could be performed.

## Example

This example creates a log file and writes the following to it:

- the string "Vuser"

- the integer "Vuser ID"

- the time, as returned by the time function.

Using fscanf, it then reads these values back into separate variables.

Copy code

        #include <stdio.h>
        #include <time.h>
        #ifdef unix
            char * filename = "/tmp/logfile.txt";
        #else
            char * filename = "c:\\logfile.txt";
        #endif
        FILE* file, thetime;
        int id, id2;
        time_t t;
        char s[32];
        // Create a new file
        if ((file = fopen(filename, "w" )) == NULL) {
            lr_output_message ("Unable to create %s", filename);
            return -1;
        }
        // Write the Vuser ID and time
        lr_whoami (&id, NULL, NULL);
        fprintf(file, "Vuser %d %ld", id, time(&t));
        // Now read what we've just written. Rewind to start of file
        rewind(file);
        fscanf(file, "%s", &s);
        fscanf(file, "%d", &id2);
        fscanf(file, "%ld", &thetime);
        lr_output_message ("%s %d %ld", s, id2, thetime);
        fclose(file);

    Example: Output:
    Vuser -1 1020675497

Tips to improve your search results... VuGen Function Reference Version 26.1-26.3 Function Reference 26.1-26.3 All View Local Help Center View Online Help Center Version: