Functions for number conversion and formatted string output.
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:
The following functions provide locale-independent string to number conversions.
Convert a string to a double. This function behaves like the Standard C function strtod does in the C locale. It does this without changing the current locale, since that would not be thread-safe.
PyOS_ascii_strtod should typically be used for reading configuration files or other non-user input that should be locale independent.
See the Unix man page strtod(2) for details.
Convert a double to a string using the '.' as the decimal separator. format is a printf-style format string specifying the number format. Allowed conversion characters are 'e', 'E', 'f', 'F', 'g' and 'G'.
The return value is a pointer to buffer with the converted string or NULL if the conversion failed.
Convert a string to a double in a locale-independent way.
See the Unix man page atof(2) for details.