braces usage without function name [duplicate] - c

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Practical use of extra braces in C
Unnecessary curly braces in C++?
What is the usage of the braces, for example as shown below:
int var;
{
some coding...
...
}
there is no function name before the braces, nor typedef, etc.
Updated:
i found this code in gwan sqlite.c example, http://gwan.com/source/sqlite.c
i partially quote it below:
...some coding
sqlite3_busy_timeout(db, 2 * 1000); // limit the joy
// -------------------------------------------------------------------------
// create the db schema and add records
// -------------------------------------------------------------------------
{ //<-- here is the starting brace
static char *TableDef[]=
{
"CREATE TABLE toons (id int primary key,"
"stamp int default current_timestamp,"
"rate int,"
"name text not null collate nocase unique,"
"photo blob);",
// you can add other SQL statements here, to add tables or records
NULL
};
sqlite3_exec(db, "BEGIN EXCLUSIVE", 0, 0, 0);
int i = 0;
do
{
if(sql_Exec(argv, db, TableDef[i]))
{
sqlite3_close(db);
return 503;
}
}
while(TableDef[++i]);
// add some records to the newly created table
sql_Exec(argv, db,
"INSERT INTO toons(rate,name) VALUES(4,'Tom'); "
"INSERT INTO toons(rate,name) VALUES(2,'Jerry'); "
"INSERT INTO toons(rate,name) VALUES(6,'Bugs Bunny'); "
"INSERT INTO toons(rate,name) VALUES(4,'Elmer Fudd'); "
"INSERT INTO toons(rate,name) VALUES(5,'Road Runner'); "
"INSERT INTO toons(rate,name) VALUES(9,'Coyote');");
sqlite3_exec(db, "COMMIT", 0, 0, 0);
// not really useful, just to illustrate how to use it
xbuf_cat(reply, "<br><h2>SELECT COUNT(*) FROM toons (HTML Format):</h2>");
sql_Query(argv, db, reply, &fmt_html, "SELECT COUNT(*) FROM toons;", 0);
} //<-- here is the ending brace
...some coding

Answer 1

Statements can be grouped into blocks, and the braces indicate the start and end of a block. A function body is a block. Blocks introduce a new variable scope that starts at the opening brace and ends at the closing brace.
What you've got there is a block.

Answer 2

braces usage without function name
I guess that rather than what it is the answer can focus on why this is done.
For example, you can re-use a variable name to do something else, using a different type (the SQLite example does this to keep using the same terminology while restarting from scratch instead of risking naming conflicts):
{
int i = 2;
...
{
int i = 10; // this is a different variable
// the old value of 'i' will be restored once this block is exited.
}
}
{
void *i = alloca(16 * 1024); // this memory will be freed automatically
... // when the block will be exited
}
But this also lets you free memory allocated on the stack with alloca(), like done above.
This is also a clear indication for the compiler that the variables defined in a block are no longer needed (this can be useful to make sure that CPU registers are freed for other tasks).
As you see, defining a scope can have cosmetic and technical uses. Both of which are useful.

Answer 3

To create a new scope for local variables within {}
for example in C:
fun(){
int i; // i -1
{
int i; // i -2 its new variable
}
}