In C90, the long data type can serve both as the largest integral type, and as a 32-bit container. C99 removes this ambiguity through the new standard library header files <inttypes.h> and <stdint.h>.

The header file <stdint.h> introduces the new types:

The header file <inttypes.h> provides library functions for manipulating values of type intmax_t, including:

intmax_t imaxabs(intmax_t x); // absolute value of x
imaxdiv_t imaxdiv(intmax_t x, intmax_t y) // returns the quotient and remainder
                                          // of x / y

These header files are also available in C90 and C++.