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copied!<p>You probably already got your hands on the <code>sqlite3</code> "Database Connection Handle" object. It is defined in <a href="http://www.sqlite.org/cgi/src/artifact/d9e42f2029d4c526f9ba960bda1980ef17429c30" rel="nofollow">sqliteInt.h</a>:</p> <pre><code>struct sqlite3 { sqlite3_vfs *pVfs; /* OS Interface */ int nDb; /* Number of backends currently in use */ Db *aDb; /* All backends */ int flags; /* Miscellaneous flags. See below */ int openFlags; /* Flags passed to sqlite3_vfs.xOpen() */ int errCode; /* Most recent error code (SQLITE_*) */ int errMask; /* & result codes with this before returning */ </code></pre> <p>You can then test for read-only with the <code>openFlags</code> member against <code>O_RDWR</code>.</p> <pre><code>#define O_RDONLY 00000000 #define O_WRONLY 00000001 #define O_RDWR 00000002 </code></pre> <p>For sure this is not the same as the newer <code>sqlite3_db_readonly()</code>, but it might be enough in your context.</p> <p><strong>Edit</strong></p> <p>Following up on your comment you can do the following to "future-proof" your code:</p> <ul> <li>check if the <code>sqlite3</code> struct varies between 3.7.0.1 and the first version that supports <code>sqlite3_db_readonly()</code></li> <li>use some macros to map the right dupe of the <code>sqlite3</code> struct (or the right offset of <code>openFlags</code>) with the corresponding 3.x.y.z version since <code>SQLITE_VERSION_NUMBER</code> is defined in sqlite3.h.</li> <li>starting with the version that supports <code>sqlite3_db_readonly()</code> just invoke it.</li> </ul> <p>Note that a database will be opened read-only if its file can only be opened for read, whether the sqlite3_open_v2 function is used with the <code>SQLITE_OPEN_READONLY</code> or not. So in addition to the aforementioned <code>openFlags</code> you'll also need to separately verify if the file can be opened read-only. The C API provides the function <code>xAccess</code> in the <code>sqlite3_vfs</code> struct. I'm guessing that this work whether your application already has a lock on the db file. See <a href="http://www.sqlite.org/c3ref/vfs.html" rel="nofollow">http://www.sqlite.org/c3ref/vfs.html</a> for more info.</p>

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