#include <stdio.h>

int main()
{
    char tmpname[L_tmpnam];
    char *filename; 
    FILE *tmpfp;

    filename = tmpnam(tmpname);

    printf("Temporary file name is: %s\n", filename);

    tmpfp = tmpfile();
    if(tmpfp)
        printf("Opened a temporary file OK\n");
    else
        perror("tmpfile");
    exit(0);
}