strtow(3c) [hpux man page]
strtod(3C) strtod(3C) NAME
strtod(), strtof(), strtold(), strtow(), strtoq(), atof() - convert string to floating-point number SYNOPSIS
Itanium(R)-based Systems Only DESCRIPTION
returns, as a double-precision floating-point number, the value represented by the character string pointed to by str. The string is scanned (leading white-space characters as defined by in ctype(3C) are ignored) up to the first unrecognized character. If no conversion can take place, zero is returned. recognizes characters in the following sequence: 1. An optional string of white space characters which are ignored 2. An optional sign and one of the following: 3. A string of digits optionally containing a radix character, followed by an optional or followed by an optional sign or space, followed by an integer 4. One of or ignoring case 5. ignoring case 6. For Itanium-based system only: or then a nonempty sequence of hexadecimal digits optionally containing a radix character, then a or followed by an optional sign or space, followed by a decimal integer The radix character is determined by the loaded environment (see setlocale(3C)). If has not been called successfully, the default environ- ment, "C", is used (see lang(5)). The default environment specifies a period as the radix character. In the hexadecimal form, the optionally signed decimal integer following the or is interpreted as the power of 2 by which the significant part is to be scaled. If the value of ptr is not the variable to which it points is set to point at the character after the last number, if any, that was recog- nized. If no number can be formed, is set to str, and zero is returned. is equivalent to is a version of it returns a result. For PA-RISC and for Itanium-based systems, if the user has defined the result type is declared as a instead of as a The declaration with a is obsolescent. Itanium-based Systems Only is a version of it returns a result. is an version of it returns an result. is equivalent to EXTERNAL INFLUENCES
Environment Variables determines the value of the radix character within the currently loaded environment. APPLICATION USAGE
To use (for Itanium-based systems) or compile with the option. RETURN VALUE
If the correct value would cause overflow, returns (equal to according to the sign of the value, and sets to If the correct value would be nonzero but too small in magnitude to represent as a nonzero then returns zero and sets to For Itanium-based system, also sets to whenever the conversion of its input parameter character string to raises the underflow exception. When the input parameter character string for after the optional white space and sign, is either (case insensitive) or (case insensitive) will return according to the sign indicated by the character string. When the input parameter character string for after the optional white space and sign, is (case insensitive), will return a quiet NaN. On Itanium-based systems, these functions round correctly for hexadecimal input strings, and round correctly for up to 36 significant deci- mal digits, according to the specification in ISO/IEC C99. SEE ALSO
ctype(3C), setlocale(3C), scanf(3S), strtol(3C), lang(5), thread_safety(5). STANDARDS CONFORMANCE
strtod(3C)
Check Out this Related Man Page
atof(3) Library Functions Manual atof(3) Name atof, atoi, atol, strtol, strtoul, strtod - convert ASCII to numbers Syntax #include <math.h> double atof(nptr) char *nptr; atoi(nptr) char *nptr; long atol(nptr) char *nptr; long strtol(nptr, eptr, base) char *nptr, **eptr; int base; unsigned long strtoul(nptr, eptr, base) char *nptr, **eptr; int base; double strtod (nptr, eptr) char *nptr, **eptr; unsigned long strtoul(nptr, eptr, base) char *nptr, **eptr; int base; Description These functions convert a string pointed to by nptr to floating, integer, and long integer representation respectively. The first unrecog- nized character ends the string. The function recognizes (in order), an optional string of spaces, an optional sign, a string of digits optionally containing a radix char- acter, an optional `e' or `E', and then an optionally signed integer. The and functions recognize (in order), an optional string of spaces, an optional sign, then a string of digits. The function returns as a long integer, the value represented by the character string nstr. The string is scanned up to the first charac- ter inconsistent with the base. Leading white-space characters are ignored. If the value of eptr is not (char **) NULL, a pointer to the character terminating the scan is returned in **eptr. If no integer can be formed, **eptr is set to nstr , and zero is returned. If base is positive and not greater than 36, it is used as the base for conversion. After an optional leading sign, leading zeros are ignored, and 0x or 0X is ignored if base is 16. If base is zero, the string itself determines the base thus: After an optional leading sign, a leading zero indicates octal conversion, and a leading 0x or 0X hexadecimal conversion. Otherwise, decimal conversion is used. Truncation from long to int can take place upon assignment, or by an explicit cast. The function is the same as except that returns, as an unsigned long integer, the value represented by the character string nstr. The function returns as a double-precision floating point number, the value represented by the character string pointed to by nptr. The string is scanned up to the first unrecognized character. The function recognizes an optional string of white-space characters, as defined by isspace in then an optional sign, then a string of dig- its optionally containing a radix character, then an optional e or E followed by an optional sign or space, followed by an integer. If the value of eptr is not (char **)NULL, a pointer to the character terminating the scan is returned in the location pointed to by eptr. If no number can be formed, *eptr is set to nptr, and zero is returned. The radix character for and is that defined by the last successful call to category If category has not been called successfully, or if the radix character is not defined for a supported language, the radix character is defined as a period (.). International Environment LC_CTYPE If this environment variable is set and valid, uses the international language database named in the definition to determine character classification rules. LC_NUMERIC If this environment is set and valid, and use the international language database named in the definition to determine radix character rules. LANG If this environment variable is set and valid and use the international language database named in the definition to deter- mine collation and character classification rules. If or is defined, their definition supercedes the definition of LANG. Diagnostics The function returns HUGE if an overflow occurs, and a 0 value if an underflow occurs, and sets errno to ERANGE. HUGE is defined in The function returns INT_MAX or INT_MIN (according to the sign of the value) and sets errno to ERANGE, if the correct value is outside the range of values that can be represented. The function returns LONG_MAX or LONG_MIN (according to the sign of the value) and sets errno to ERANGE, if the correct value is outside the range of values that can be represented. The function returns LONG_MAX or LONG_MIN (according to the sign of the value) and sets errno to ERANGE, if the correct value is outside the range of values that can be represented. The function returns ULONG_MAX and sets errno to ERANGE, if the correct value is outside the range of values that can be represented. The function returns HUGE (according to the sign of the value), and sets errno to ERANGE if the correct value would cause overflow. A 0 is returned and errno is set to ERANGE if the correct value would cause underflow. See Also ctype(3), setlocale(3), scanf(3s), environ(5int) atof(3)