C API Function Descriptions
2151
Example
The following example shows how you might use
mysql_eof()
:
mysql_query(&mysql,"SELECT * FROM some_table");
result = mysql_use_result(&mysql);
while((row = mysql_fetch_row(result)))
{
// do something with data
}
if(!mysql_eof(result)) // mysql_fetch_row() failed due to an error
{
fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
}
However, you can achieve the same effect with the standard MySQL error functions:
mysql_query(&mysql,"SELECT * FROM some_table");
result = mysql_use_result(&mysql);
while((row = mysql_fetch_row(result)))
{
// do something with data
}
if(mysql_errno(&mysql)) // mysql_fetch_row() failed due to an error
{
fprintf(stderr, "Error: %s\n", mysql_error(&mysql));
}
20.6.6.14.
mysql_errno()
unsigned int mysql_errno(MYSQL *mysql)
Description
For the connection specified by
mysql
,
mysql_errno()
returns the error code for the most recently
invoked API function that can succeed or fail. A return value of zero means that no error occurred.
Client error message numbers are listed in the MySQL
errmsg.h
header file. Server error message
numbers are listed in
mysqld_error.h
. Errors also are listed at
Appendix C, Errors, Error Codes, and
Common Problems
.
Note that some functions like
mysql_fetch_row()
don't set
mysql_errno()
if they succeed.
A rule of thumb is that all functions that have to ask the server for information reset
mysql_errno()
if
they succeed.
MySQL-specific error numbers returned by
mysql_errno()
differ from SQLSTATE values
returned by
mysql_sqlstate()
. For example, the
mysql
client program displays errors using
the following format, where
1146
is the
mysql_errno()
value and
'42S02'
is the corresponding
mysql_sqlstate()
value:
shell>
SELECT * FROM no_such_table;
ERROR 1146 (42S02): Table 'test.no_such_table' doesn't exist
Return Values
An error code value for the last
mysql_xxx()
call, if it failed. zero means no error occurred.
Errors
None.
20.6.6.15.
mysql_error()
const char *mysql_error(MYSQL *mysql)
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