Add date and time to a file name in c

Question

Im looking for a way to add the current date and time to a log file im opening for now im using :

fopen("/var/log/SA_TEST","w");

How to make it

fopen("/var/log/SA_TEST_DATE_AND_TIME","w");

Thx a lot (In c)

Answer 1

strftime can be used to format the date an time :

#include <time.h>

char filename[40];
struct tm *timenow;

time_t now = time(NULL);
timenow = gmtime(&now);

strftime(filename, sizeof(filename), "/var/log/SA_TEST_%Y-%m-%d_%H:%M:%S", timenow);

fopen(filename,"w");

You can change the date an time format for whatever you want according to the strftime manual.

You can use the timestamp as 'compact format' with the result of time only.

sprintf(filename, "/var/log/SA_TEST_%d", (int)now);