Functions for number conversion and formatted string output.
PyOS_snprintf(char *str, size_t size, const char *format, ...)PyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)PyOS_snprintf() and PyOS_vsnprintf() wrap the Standard C library
functions snprintf() and vsnprintf(). Their purpose is to
guarantee consistent behavior in corner cases, which the Standard C functions do
not.
The wrappers ensure that str*[*size-1] is always '\0' upon return. They
never write more than size bytes (including the trailing '\0') into str.
Both functions require that str != NULL, size > 0 and format != NULL.
If the platform doesn’t have vsnprintf() and the buffer size needed to
avoid truncation exceeds size by more than 512 bytes, Python aborts with a
Py_FatalError().
The return value (rv) for these functions should be interpreted as follows:
0 <= rv < size, the output conversion was successful and rv characters were written to str (excluding the trailing '\0' byte at str*[*rv]).rv >= size, the output conversion was truncated and a buffer with rv + 1 bytes would have been needed to succeed. str*[*size-1] is '\0' in this case.rv < 0, “something bad happened.” str*[*size-1] is '\0' in this case too, but the rest of str is undefined. The exact cause of the error depends on the underlying platform.The following functions provide locale-independent string to number conversions.
PyOS_string_to_double(const char *s, char **endptr, PyObject *overflow_exception)Convert a string s to a double, raising a Python
exception on failure. The set of accepted strings corresponds to
the set of strings accepted by Python’s float() constructor,
except that s must not have leading or trailing whitespace.
The conversion is independent of the current locale.
If endptr is NULL, convert the whole string. Raise
ValueError and return -1.0 if the string is not a valid
representation of a floating-point number.
If endptr is not NULL, convert as much of the string as
possible and set *endptr to point to the first unconverted
character. If no initial segment of the string is the valid
representation of a floating-point number, set *endptr to point
to the beginning of the string, raise ValueError, and return
-1.0.
If s represents a value that is too large to store in a float
(for example, "1e500" is such a string on many platforms) then
if overflow_exception is NULL return Py_HUGE_VAL (with
an appropriate sign) and don’t set any exception. Otherwise,
overflow_exception must point to a Python exception object;
raise that exception and return -1.0. In both cases, set
*endptr to point to the first character after the converted value.
If any other error occurs during the conversion (for example an
out-of-memory error), set the appropriate Python exception and
return -1.0.
New in version 3.1.
PyOS_double_to_string(double val, char format_code, int precision, int flags, int *ptype)Convert a double val to a string using supplied
format_code, precision, and flags.
format_code must be one of 'e', 'E', 'f', 'F',
'g', 'G' or 'r'. For 'r', the supplied precision
must be 0 and is ignored. The 'r' format code specifies the
standard repr() format.
flags can be zero or more of the values Py_DTSF_SIGN,
Py_DTSF_ADD_DOT_0, or Py_DTSF_ALT, or-ed together:
Py_DTSF_SIGN means to always precede the returned string with a sign
character, even if val is non-negative.
Py_DTSF_ADD_DOT_0 means to ensure that the returned string will not look
like an integer.
Py_DTSF_ALT means to apply “alternate” formatting rules. See the
documentation for the PyOS_snprintf() '#' specifier for
details.
If ptype is non-NULL, then the value it points to will be set to one of
Py_DTST_FINITE, Py_DTST_INFINITE, or Py_DTST_NAN, signifying that
val is a finite number, an infinite number, or not a number, respectively.
The return value is a pointer to buffer with the converted string or
NULL if the conversion failed. The caller is responsible for freeing the
returned string by calling PyMem_Free().
New in version 3.1.
PyOS_stricmp(const char *s1, const char *s2)strcmp() except that it ignores the case.PyOS_strnicmp(const char *s1, const char *s2, Py_ssize_t size)strncmp() except that it ignores the case.