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(mysql.info)mysql_store_result

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`mysql_store_result()'
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`MYSQL_RES *mysql_store_result(MYSQL *mysql)'

Description
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You must call `mysql_store_result()' or `mysql_use_result()' for every
query that successfully retrieves data (`SELECT', `SHOW', `DESCRIBE',
`EXPLAIN').

You don't have to call `mysql_store_result()' or `mysql_use_result()'
for other queries, but it will not do any harm or cause any notable
performance if you call `mysql_store_result()' in all cases.  You can
detect if the query didn't have a result set by checking if
`mysql_store_result()' returns 0 (more about this later one).

If you want to know if the query should return a result set or not, you
can use `mysql_field_count()' to check for this.  Note:
`mysql_field_count'.

`mysql_store_result()' reads the entire result of a query to the client,
allocates a `MYSQL_RES' structure, and places the result into this
structure.

`mysql_store_results()' returns a null pointer if the query didn't
return a result set (if the query was, for example, an `INSERT'
statement).

`mysql_store_results()' also returns a null pointer if reading of the
result set failed. You can check if you got an error by checking if
`mysql_error()' doesn't return a null pointer, if `mysql_errno()'
returns <> 0, or if `mysql_field_count()' returns <> 0.

An empty result set is returned if there are no rows returned.  (An
empty result set differs from a null pointer as a return value.)

Once you have called `mysql_store_result()' and got a result back that
isn't a null pointer, you may call `mysql_num_rows()' to find out how
many rows are in the result set.

You can call `mysql_fetch_row()' to fetch rows from the result set, or
`mysql_row_seek()' and `mysql_row_tell()' to obtain or set the current
row position within the result set.

You must call `mysql_free_result()' once you are done with the result
set.

Note: `NULL mysql_store_result()'.

Return Values
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A `MYSQL_RES' result structure with the results. `NULL' if an error
occurred.

Errors
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`CR_COMMANDS_OUT_OF_SYNC'
     Commands were executed in an improper order.

`CR_OUT_OF_MEMORY'
     Out of memory.

`CR_SERVER_GONE_ERROR'
     The MySQL server has gone away.

`CR_SERVER_LOST'
     The connection to the server was lost during the query.

`CR_UNKNOWN_ERROR'
     An unknown error occurred.