strtol

Converts strings of ASCII characters to the appropriate numeric values.

Format 

#include  <stdlib.h>

long int strtol  (const char *nptr, char **endptr,
                 int base);
Function Variants This function also has variants named _strtol32 and _strtol64 for use with 32-bit and 64-bit pointer sizes, respectively. See Section 1.8 for more information on using pointer-size-specific functions.

Arguments

nptr
A pointer to the character string to be converted to a long.
endptr
The address of an object where the function can store a pointer to the first unrecognized character encountered in the conversion process (that is, the character that follows the last character in the string being converted). If endptr is a NULL pointer, the address of the first unrecognized character is not retained.
base
The value, 2 through 36, to use as the base for the conversion.

Description

This function recognizes strings in various formats, depending on the value of the base. This function ignores any leading white- space characters (as defined by isspace in <ctype.h>) in the given string. It recognizes an optional plus or minus sign, then a sequence of digits or letters that may represent an integer constant according to the value of the base. The first unrecognized character ends the conversion.

Leading zeros after the optional sign are ignored, and 0x or 0X is ignored if the base is 16.

If base is 0, the sequence of characters is interpreted by the same rules used to interpret an integer constant: after the optional sign, a leading 0 indicates octal conversion, a leading 0x or 0X indicates hexadecimal conversion, and any other combination of leading characters indicates decimal conversion.

Truncation from long to int can take place after assignment or by an explicit cast (arithmetic exceptions not withstanding). The function call atol (str) is equivalent to strtol (str, (char**)NULL, 10).

Return Values
x  The converted value. 
LONG_MAX or LONG_MIN  Indicates that the converted value would cause an overflow. 
0  Indicates that the string starts with an unrecognized character or that the value for base is invalid. If the string starts with an unrecognized character, *endptr is set to nptr. 

strtoq, strtoll (Alpha only)

Converts strings of ASCII characters to the appropriate numeric values. strtoll is a synonym for strtoq.

Format 

#include  <stdlib.h>

__int64 strtoq  (const char *nptr, char **endptr,
                int base);

__int64 strtoll  (const char *nptr, char **endptr,
                 int base);
Function Variants This function also has variants named _strtoq32/_strtoll32 and _ strtoq64/_strtoll64 for use with 32-bit and 64-bit pointer sizes, respectively. See Section 1.8 for more information on using pointer-size-specific functions.

Arguments

nptr
A pointer to the character string to be converted to an __int64.
endptr
The address of an object where the function can store a pointer to the first unrecognized character encountered in the conversion process (that is, the character that follows the last character in the string being converted). If endptr is a NULL pointer, the address of the first unrecognized character is not retained.
base
The value, 2 through 36, to use as the base for the conversion.

Description

This function recognizes strings in various formats, depending on the value of the base. This function ignores any leading white- space characters (as defined by isspace in <ctype.h>) in the given string. It recognizes an optional plus or minus sign, then a sequence of digits or letters that may represent an integer constant according to the value of the base. The first unrecognized character ends the conversion.

Leading zeros after the optional sign are ignored, and 0x or 0X is ignored if the base is 16.

If base is 0, the sequence of characters is interpreted by the same rules used to interpret an integer constant: after the optional sign, a leading 0 indicates octal conversion, a leading 0x or 0X indicates hexadecimal conversion, and any other combination of leading characters indicates decimal conversion.

The function call atoq (str) is equivalent to strtoq (str, (char**)NULL, 10).

Return Values
x  The converted value. 
__INT64_MAX or __INT64_MIN  Indicates that the converted value would cause an overflow. 
0  Indicates that the string starts with an unrecognized character or that the value for base is invalid. If the string starts with an unrecognized character, *endptr is set to nptr. 

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