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SQLite C Interface
Obtain Values For URI Parameters
const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
These are utility routines, useful to VFS implementations, that check to see if a database file was a URI that contained a specific query parameter, and if so obtains the value of that query parameter.
If F is the database filename pointer passed into the xOpen() method of a VFS implementation when the flags parameter to xOpen() has one or more of the SQLITE_OPEN_URI or SQLITE_OPEN_MAIN_DB bits set and P is the name of the query parameter, then sqlite3_uri_parameter(F,P) returns the value of the P parameter if it exists or a NULL pointer if P does not appear as a query parameter on F. If P is a query parameter of F has no explicit value, then sqlite3_uri_parameter(F,P) returns a pointer to an empty string.
The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean parameter and returns true (1) or false (0) according to the value of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the value of query parameter P is one of "yes", "true", or "on" in any case or if the value begins with a non-zero number. The sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of query parameter P is one of "no", "false", or "off" in any case or if the value begins with a numeric zero. If P is not a query parameter on F or if the value of P is does not match any of the above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 64-bit signed integer and returns that integer, or D if P does not exist. If the value of P is something other than an integer, then zero is returned.
If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and is not a database file pathname pointer that SQLite passed into the xOpen VFS method, then the behavior of this routine is undefined and probably undesirable.