Computer Science
STRTOL(3) Linux Programmer's Manual STRTOL(3)
NAME
strtol - convert a string to a long integer.
SYNOPSIS
#include <stdlib.h>
long int strtol(const char *nptr, char **endptr, int base);
DESCRIPTION
The strtol() function converts the string in 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 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 may then include a `0x' prefix, and the number will
be read in base 16; otherwise, a zero base is taken as 10
(decimal) unless the next character is `0', in which case
it is taken as 8 (octal).
The remainder of the string is converted to a long int
value in the obvious manner, stopping at the first charac-
ter which is not a valid digit in the given base. (In
bases above 10, the letter `A' in 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 *endptr. If there were no dig-
its at all, strtol() stores the original value of nptr in
*endptr. (Thus, if *nptr is not `\0' but **endptr is `\0'
on return, the entire string is valid.)
RETURN VALUE
The strtol() function returns the result of the conver-
sion, unless the value would underflow or overflow. If an
underflow occurs, strtol() returns LONG_MIN. If an over-
flow occurs, strtol() returns LONG_MAX. In both cases,
errno is set to ERANGE.
ERRORS
ERANGE The given string was out of range; the value con-
verted has been clamped.
CONFORMING TO
SVID 3, BSD 4.3, ISO 9899
SEE ALSO
atof(3), atoi(3), atol(3), strtod(3), strtoul(3)
BUGS
Ignores the current locale.
GNU 10 June 1995 1
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