Why is lltostr() reported as undefined when I try to compile Solaris code on Linux?

The lltostr() function is a function provided on Solaris to convert a long long value to a string.The lltostr function is not provided on Linux systems but the same functionality can easily be achieved by using sprintf. For example:

sprintf (string, "%lld", long_long_value);

Alternatively if you really want to continue to use lltostr() in your code then the good news is that the source for the function is now available under Sun's Open Solaris initiative. You can get the source for lltostr from the following URL:

https://cvs.opensolaris.org/source/xref/usr/src/lib/libc/port/gen/lltostr.c

Before porting this code and linking it with your application make sure you are in compliance with the source license under which this code is made available.