atoi, atol, atoll - 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);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
atoll():
_ISOC99_SOURCE ||
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
The
atoi() function converts the initial portion of the string pointed to
by
nptr to
int. The behavior is the same as
strtol(nptr, 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.
The converted value.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| atoi (), atol (), atoll () |
Thread safety |
MT-Safe locale |
POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD. C89 and POSIX.1-1996 include the
functions
atoi() and
atol() only.
atof(3),
strtod(3),
strtol(3),
strtoul(3)