Question

With int snprintf(char *str, size_t size, const char *format, ...);
I can write specific number of characters into str .

How can I read specific number of characters from a c-string ?

Regards

Answer 1

You can pass a number in the format argument:

char buf[21];
sscanf(str, "%20s", buf);

This reads up to 20 characters into the buf.

If you do not know how much data you are going to read at compile time, you can prepare the format string at runtime:

char format[20];
sprintf(format, "%%%ds", howMuchToRead);
sscanf(str, format, buf);