C++ Programming/Code/Standard C Library/Functions/atol< C++ Programming | Code/Standard C Library | Functions
#include <cstdlib> long atol( const char *str );
The function atol() converts str into a long, then returns that value. atol() will read from str until it finds any character that should not be in a long. The resulting truncated value is then converted and returned. For example,
x = atol( "1024.0001" );
results in x being set to 1024L.