strtoimax, strtoumax
Defined in header <inttypes.h>


intmax_t strtoimax( const char *restrict nptr, char **restrict endptr, int base ); 
(since C99)  
uintmax_t strtoumax( const char *restrict nptr, char **restrict endptr, int base ); 
(since C99)  
Interprets an integer value in a byte string pointed to by nptr
.
Function discards any whitespace characters (as identified by calling isspace()
) until first nonwhitespace character is found. Then it takes as many characters as possible to form a valid basen (where n=base) integer number representation and converts them to an integer value. The valid integer value consists of the following parts:
 (optional) plus or minus sign
 (optional) prefix (
0
) indicating octal base (applies only when the base is 8 or 0)  (optional) prefix (
0x
or0X
) indicating hexadecimal base (applies only when the base is 16 or 0)  a sequence of digits
The set of valid digits for base2 integer is 01
, for base3 integer is 012
, and so on. For bases larger than 10
, valid digits include alphabetic characters, starting from Aa
for base11 integer, to Zz
for base36 integer. The case of the characters is ignored.
Additional numeric formats may be accepted by the currently installed C locale.
If the value of base is 0, the numeric base is autodetected: if the prefix is 0
, the base is octal, if the prefix is 0x
or 0X
, the base is hexadecimal, otherwise the base is decimal.
If the minus sign was part of the input sequence, the numeric value calculated from the sequence of digits is negated in the result type.
The functions sets the pointer pointed to by endptr
to point to the character past the last character interpreted. If endptr
is NULL, it is ignored.
If the nptr
is empty or does not have the expected form, no conversion is performed, and (if enptr
is not NULL) the value of nptr
is stored in the object pointed to by endptr
.
Contents 
Parameters
nptr    pointer to the nullterminated byte string to be interpreted 
endptr    pointer to a pointer to character. 
base    base of the interpreted integer value 
Return value
 If successful, an integer value corresponding to the contents of
str
is returned.  If the converted value falls out of range of corresponding return type, a range error occurs (setting [[cpp/error/errnoerrno]] to ERANGE) and INTMAX_MAX, INTMAX_MIN, UINTMAX_MAX or 0 is returned, as appropriate.
 If no conversion can be performed, 0 is returned.
Example
This section is incomplete Reason: example 
See also
(C99)(C99) 
converts a wide string to intmax_t or uintmax_t (function) 
converts a byte string to an integer value (function)  
converts a byte string to an unsigned integer value (function)  
C++ documentation for strtoimax, strtoumax
