STRTOL(3) Linux Programmer's Manual STRTOL(3)
NAME
strtol, strtoll, strtoq - convert a string(3,n) to a long integer
SYNOPSIS
#include <stdlib.h>
long int
strtol(const char *nptr, char **endptr, int base);
long long int
strtoll(const char *nptr, char **endptr, int base);
DESCRIPTION
The strtol() function converts the initial part of the string(3,n) in(1,8) nptr
to a long integer value according to the given base, which must be
between 2 and 36 inclusive, or be the special value 0.
The string(3,n) must begin with an arbitrary amount of white space (as
determined by isspace(3)) followed by a single optional `+' or `-'
sign. If base is zero or 16, the string(3,n) may then include a `0x' pre-
fix, and the number will be read(2,n,1 builtins) in(1,8) base 16; otherwise, a zero base is
taken as 10 (decimal) unless the next character is `0', in(1,8) which case
it is taken as 8 (octal).
The remainder of the string(3,n) is converted to a long int value in(1,8) the
obvious manner, stopping at the first character which is not a valid
digit in(1,8) the given base. (In bases above 10, the letter `A' in(1,8) either
upper or lower case represents 10, `B' represents 11, and so forth,
with `Z' representing 35.)
If endptr is not NULL, strtol() stores the address of the first invalid
character in(1,8) *endptr. If there were no digits at all, strtol() stores
the original value of nptr in(1,8) *endptr (and returns 0). In particular,
if(3,n) *nptr is not `\0' but **endptr is `\0' on return, the entire string(3,n)
is valid.
The strtoll() function works just like the strtol() function but
returns a long long integer value.
RETURN VALUE
The strtol() function returns the result of the conversion, unless the
value would underflow or overflow. If an underflow occurs, strtol()
returns LONG_MIN. If an overflow occurs, strtol() returns LONG_MAX.
In both cases, errno is set(7,n,1 builtins) to ERANGE. Precisely the same holds for
strtoll() (with LLONG_MIN and LLONG_MAX instead of LONG_MIN and
LONG_MAX).
ERRORS
EINVAL (not in(1,8) C99) The given base contains an unsupported value.
ERANGE The resulting value was out of range.
The implementation may also set(7,n,1 builtins) errno to EINVAL in(1,8) case no conversion
was performed (no digits seen, and 0 returned).
NOTES
In locales other than the "C" locale(3,5,7), also other strings may be
accepted. (For example, the thousands separator of the current locale(3,5,7)
may be supported.)
BSD also has
quad_t
strtoq(const char *nptr, char **endptr, int base);
with completely analogous definition. Depending on the wordsize of the
current architecture, this may be equivalent to strtoll() or to str-
tol().
CONFORMING TO
strtol() conforms to SVID 3, BSD 4.3, ISO 9899 (C99) and POSIX, and
strtoll() to ISO 9899 (C99) and POSIX 1003.1-2001.
SEE ALSO
atof(3), atoi(3), atol(3), strtod(3), strtoul(3)
GNU 2002-05-30 STRTOL(3)