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       atoi, atol, atoll, atoq - convert a string to an integer


       #include <stdlib.h>

       int atoi(const char *nptr);
       long atol(const char *nptr);
       long long atoll(const char *nptr);
       long long atoq(const char *nptr);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       atoll(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 ||
       _ISOC99_SOURCE; or cc -std=c99


       The atoi() function converts the initial portion of the string  pointed
       to by nptr to int.  The behavior is the same as

           strtol(nptr, (char **) NULL, 10);

       except that atoi() does not detect errors.

       The atol() and atoll() functions behave the same as atoi(), except that
       they convert the initial portion of the string to their return type  of
       long or long long.  atoq() is an obsolete name for atoll().


       The converted value.


       SVr4,  POSIX.1-2001,  4.3BSD,  C99.   C89  and POSIX.1-1996 include the
       functions atoi() and atol() only.  atoq() is a GNU extension.


       The nonstandard atoq() function is not present in libc 4.6.27 or  glibc
       2,  but  is  present  in  libc5  and libc 4.7 (though only as an inline
       function in <stdlib.h> until libc 5.4.44).   The  atoll()  function  is
       present in glibc 2 since version 2.0.2, but not in libc4 or libc5.


       atof(3), strtod(3), strtol(3), strtoul(3)


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