##### Synopsis

    #include <stdlib.h>
    int atoi(const char *nptr);

##### Description

atoi converts the initial portion of the string pointed to by nptr to an int representation.

atoi does not affect the value of errno on an error. If the value of the result cannot be represented, the behavior is undefined.

Except for the behavior on error, atoi is equivalent to `(int)strtol(nptr, (char **)NULL, 10)`.

atoi returns the converted value.

##### Portability

atoi conforms to ISO/IEC 9899:1990 (C90) and ISO/IEC 9899:1999 (C99).