Miscellaneous Functions

Table 17-7 lists the miscellaneous OCI functions that are described in this section.

OCIBreak()

Purpose

Performs an immediate (asynchronous) termination of any currently executing OCI function that is associated with a server.

Syntax

sword OCIBreak ( void       *hndlp,
                 OCIError   *errhp );

Parameters

hndlp (IN/OUT)

The service context handle or the server context handle.

errhp (IN/OUT)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

Comments

This call performs an immediate (asynchronous) termination of any currently executing OCI function that is associated with a server. It is normally used to stop a long-running OCI call being processed on the server. It can be called by a user thread in multithreaded applications, or by a user signal handler on Linux or UNIX systems. OCIBreak() is the only OCI call allowed in a user signal handler.

This call can take either the service context handle or the server context handle as a parameter to identify the function to be terminated.

Related Functions

OCIReset()

OCIClientVersion()

Purpose

Returns the 5 digit Oracle Database version number of the client library at run time.

Syntax

sword OCIClientVersion ( sword        *major_version, 
                         sword        *minor_version, 
                         sword        *update_num,
                         sword        *patch_num,
                         sword        *port_update_num );

Parameters

major_version (OUT)

The major version.

minor_version (OUT)

The minor version.

update_num (OUT)

The update number.

patch_num (OUT)

The patch number that was applied to the library.

port_update_num (OUT)

The port-specific patch applied to the library.

Comments

OCIClientVersion() returns the version of OCI client that the application is running with. This is useful for the application to know at run time. An application or a test program can determine the version and the patch set of a particular OCI client installation by calling this function. This is also useful if the application wants to have different codepaths depending upon the level of the client patchset.

In addition to OCIClientVersion() there are two macros defined: OCI_MAJOR_VERSION and OCI_MINOR_VERSION. These are useful for writing a generic application that can be built and run with different versions of OCI client. For example:

....
#if (OCI_MAJOR_VERSION > 9)
...
#endif
....

Related Functions

OCIServerRelease()

OCIErrorGet()

Purpose

Returns an error message in the buffer provided and an Oracle Database error code.

Syntax

sword OCIErrorGet ( void       *hndlp, 
                    ub4        recordno,
                    OraText    *sqlstate,
                    sb4        *errcodep, 
                    OraText    *bufp,
                    ub4        bufsiz,
                    ub4        type );

Parameters

hndlp (IN)

The error handle, usually, or the environment handle (for errors on OCIEnvCreate(), OCIHandleAlloc()).

recordno (IN)

Indicates the status record from which the application seeks information. Starts from 1.

sqlstate (OUT)

Not supported in release 8.x or later.

errcodep (OUT)

The error code returned.

bufp (OUT)

The error message text returned.

bufsiz (IN)

The size of the buffer provided for the error message, in number of bytes. If the error message length is more than bufsiz, a truncated error message text is returned in bufp.

If type is set to OCI_HTYPE_ERROR, then the return code during truncation for OCIErrorGet() is OCI_ERROR. The client can then specify a bigger buffer and call OCIErrorGet() again.

If bufsiz is sufficient to hold the entire message text and the message could be successfully copied into bufp, the return code for OCIErrorGet() is OCI_SUCCESS.

type (IN)

The type of the handle (OCI_HTYPE_ERROR or OCI_HTYPE_ENV).

Comments

This function does not support SQL statements. Usually, hndlp is actually the error handle, or the environment handle. You should always get the message in the encoding that was set in the environment handle. This function can be called multiple times if there are multiple diagnostic records for an error.

Note that OCIErrorGet() must not be called when the return code is OCI_SUCCESS. Otherwise, an error message from a previously executed statement is found by OCIErrorGet().

The error handle is originally allocated with a call to OCIHandleAlloc().

Example

Example 17-6 shows a simplified example of a function for error checking using OCIErrorGet().

static void checkerr(OCIError *errhp, sword status)
{
  text errbuf[512];
  ub4 buflen;
  sb4 errcode;

  if (status == OCI_SUCCESS) return;

  switch (status)
  {
  case OCI_SUCCESS_WITH_INFO:
    printf("Error - OCI_SUCCESS_WITH_INFO\n");
    OCIErrorGet ((void  *) errhp, (ub4) 1, (text *) NULL, &errcode,
            errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
    printf("Error - %s\n", errbuf);
    break;
  case OCI_NEED_DATA:
    printf("Error - OCI_NEED_DATA\n");
    break;
  case OCI_NO_DATA:
    printf("Error - OCI_NO_DATA\n");
    break;
  case OCI_ERROR:
    OCIErrorGet ((void  *) errhp, (ub4) 1, (text *) NULL, &errcode,
            errbuf, (ub4) sizeof(errbuf), (ub4) OCI_HTYPE_ERROR);
    printf("Error - %s\n", errbuf);
    break;
  case OCI_INVALID_HANDLE:
    printf("Error - OCI_INVALID_HANDLE\n");
    break;
  case OCI_STILL_EXECUTING:
    printf("Error - OCI_STILL_EXECUTING\n");
    break;
  case OCI_CONTINUE:
    printf("Error - OCI_CONTINUE\n");
    break;
  default:
    printf("Error - %d\n", status);
    break;
  }
}

Related Functions

OCIHandleAlloc()

OCILdaToSvcCtx()

Purpose

Converts a V7 Lda_Def to a V8 or later service context handle.

Syntax

sword OCILdaToSvcCtx ( OCISvcCtx  **svchpp,
                       OCIError   *errhp,
                       Lda_Def    *ldap );

Parameters

svchpp (IN/OUT)

The service context handle.

errhp (IN/OUT)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

ldap (IN/OUT)

The Oracle7 logon data area returned by OCISvcCtxToLda() from this service context.

Comments

Converts an Oracle7 Lda_Def to a release 8 or later service context handle. The action of this call can be reversed by passing the resulting service context handle to the OCISvcCtxToLda() function.

You should use the OCILdaToSvcCtx() call only for resetting an Lda_Def obtained from OCISvcCtxToLda() back to a service context handle. It cannot be used to transform an Lda_def that started as an Lda_def back to a service context handle.

If the service context has been converted to an Lda_Def, only Oracle7 calls can be used. It is illegal to make OCI release 8 or later calls without first resetting the Lda_Def to a service context.

The OCI_ATTR_IN_V8_MODE attribute of the server handle or service context handle enables an application to determine whether the application is currently in Oracle release 7 mode or Oracle release 8 or later mode.

Related Functions

OCISvcCtxToLda()

OCIPasswordChange()

Purpose

Allows the password of an account to be changed.

Syntax

sword OCIPasswordChange ( OCISvcCtx     *svchp,
                          OCIError      *errhp,
                          const OraText *user_name,
                          ub4           usernm_len,
                          const OraText *opasswd,
                          ub4           opasswd_len,
                          const OraText *npasswd,
                          sb4           npasswd_len,
                          ub4           mode );

Parameters

svchp (IN/OUT)

A handle to a service context. The service context handle must be initialized and have a server context handle associated with it.

errhp (IN)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

user_name (IN)

Specifies the user name, which can be in UTF-16 encoding. It must be terminated with a NULL character if the service context has been initialized with an authentication handle.

usernm_len (IN)

The length of the user name string specified in user_name, in number of bytes regardless of the encoding. The usernm_len value must be nonzero.

opasswd (IN)

Specifies the user's old password, which can be in UTF-16 encoding.

opasswd_len (IN)

The length of the old password string specified in opasswd, in bytes. The opasswd_len value must be nonzero.

npasswd (IN)

Specifies the user's new password, which can be in UTF-16 encoding. If the password complexity verification routine is specified in the user's profile to verify the new password's complexity, the new password must meet the complexity requirements of the verification function.

npasswd_len (IN)

The length in bytes of the new password string specified in npasswd. For a valid password string, npasswd_len must be nonzero.

mode (IN)

OCI_DEFAULT - Use the setting in the environment handle.

• OCI_UTF16 - Use UTF-16 encoding, regardless of the setting of the environment handle.

  There is only one encoding allowed, either UTF-16 or not, for user_name, opasswd, and npasswd.

• OCI_AUTH - If a user session context is not created, a call with this flag creates the user session context and changes the password. At the end of the call, the user session context is not cleared. Hence the user remains logged in.

  If the user session context is created, a call with this flag only changes the password and has no effect on the session. Hence the user still remains logged in.

Comments

This call allows the password of an account to be changed. This call is similar to OCISessionBegin() with the following differences:

• If the user session is established, this call authenticates the account using the old password and then changes the password to the new password.

• If the user session is not established, this call establishes a user session and authenticates the account using the old password, and then changes the password to the new password.

This call is useful when the password of an account has expired and OCISessionBegin() returns an error (ORA-28001) or warning that indicates that the password has expired.

The mode or the environment handle determines if UTF-16 is being used.

Related Functions

OCISessionBegin()

OCIPing()

Purpose

Makes a round-trip call to the server to confirm that the connection and the server are active.

Syntax

sword OCIPing ( OCISvcCtx     *svchp,
                OCIError      *errhp,
                ub4           mode );

Parameters

svchp (IN)

A handle to a service context. The service context handle must be initialized and have a server context handle associated with it.

errhp (IN)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

mode (IN)

The mode for the call. Use OCI_DEFAULT.

Comments

OCIPing() makes a dummy round-trip call to the server; that is, a dummy packet is sent to the server for response. OCIPing() returns after the round-trip is completed. No server operation is performed for this call itself.

You can use OCIPing() to make a lightweight call to the server. A successful return of the call indicates that the connection and server are active. If the call blocks, the connection may be in use by other threads. If it fails, there may be some problem with the connection or the server, and the error can be retrieved from the error handle. Because OCIPing() is a round-trip call, you can also use it to flush all the pending OCI client-side calls to the server, if any exist. For example, calling OCIPing() after OCIHandleFree() can force the execution of the pending call to close back-end cursors. The call is useful when the application requires the back-end cursors to be closed immediately.

Related Functions

OCIHandleFree()

OCIReset()

Purpose

Resets the interrupted asynchronous operation and protocol. Must be called if an OCIBreak() call was issued while a nonblocking operation was in progress.

Syntax

sword OCIReset ( void       *hndlp,
                 OCIError   *errhp );

Parameters

hndlp (IN)

The service context handle or the server context handle.

errhp (IN)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

Comments

This call is called in nonblocking mode only. It resets the interrupted asynchronous operation and protocol. OCIReset() must be called if an OCIBreak() call was issued while a nonblocking operation was in progress.

Related Functions

OCIBreak()

OCIRowidToChar()

Purpose

Converts a Universal ROWID to character extended (base 64) representation.

Syntax

sword OCIRowidToChar ( OCIRowid      *rowidDesc,
                       OraText       *outbfp,
                       ub2           *outbflp
                       OCIError      *errhp );

Parameters

rowidDesc (IN)

The ROWID descriptor that is allocated by OCIDescriptorAlloc() and populated by a prior execution of a SQL statement.

outbfp (OUT)

Pointer to the buffer where the character representation is stored after successful execution of this call.

outbflp (IN/OUT)

Pointer to the output buffer length. Before execution, the buffer length contains the size of outbfp. After execution it contains the number of bytes converted.

If there is truncation during conversion, outbfp contains the length required to make conversion successful. An error is also returned.

errhp (IN)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

Comments

After this conversion, the ROWID in character format can be bound with the OCIBindByPos() or OCIBindByName() calls, and used to query a row at the given ROWID.

OCIServerRelease()

Purpose

Returns the Oracle Database release string.

Syntax

sword OCIServerRelease ( void         *hndlp, 
                         OCIError     *errhp, 
                         OraText      *bufp,
                         ub4          bufsz
                         ub1          hndltype 
                         ub4          *version );

Parameters

hndlp (IN)

The service context handle or the server context handle.

errhp (IN/OUT)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

bufp (IN/OUT)

The buffer in which the release string is returned.

bufsz (IN)

The length of the buffer in number of bytes.

hndltype (IN)

The type of handle passed to the function.

version (IN/OUT)

The release string in integer format.

Comments

The buffer pointer bufp points to the release information in a string representation up to the bufsz including the NULL terminator. If the buffer size is too small, the result is truncated to the size bufsz. The version argument contains the 5-digit Oracle Database release string in integer format, which can be retrieved using the following macros:

#define MAJOR_NUMVSN(v) ((sword)(((v) >> 24) & 0x000000FF))      /* version number */ 
#define MINOR_NUMRLS(v) ((sword)(((v) >> 20) & 0x0000000F))      /* release number */
#define UPDATE_NUMUPD(v) ((sword)(((v) >> 12) & 0x000000FF))     /* update number */ 
#define PORT_REL_NUMPRL(v) ((sword)(((v) >> 8) & 0x0000000F))    /* port release number */ 
#define PORT_UPDATE_NUMPUP(v) ((sword)(((v) >> 0) & 0x000000FF)) /* port update number */

Related Functions

OCIServerVersion()

OCIServerVersion()

Purpose

Returns the Oracle Database version string.

Syntax

sword OCIServerVersion ( void         *hndlp, 
                         OCIError     *errhp, 
                         OraText      *bufp,
                         ub4          bufsz
                         ub1          hndltype );

Parameters

hndlp (IN)

The service context handle or the server context handle.

errhp (IN/OUT)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

bufp (IN/OUT)

The buffer in which the version information is returned.

bufsz (IN)

The length of the buffer in number of bytes.

hndltype (IN)

The type of handle passed to the function.

Comments

This call returns the version string of Oracle Database. It can be in Unicode if the environment handle so determines.

For example, the following is returned in bufp as the version string if an application is running on an 8.1.5 SunOS server:

Oracle8i Enterprise Edition Release 8.1.5.0.0 - Production
With the Partitioning and Java options
PL/SQL Release 8.1.5.0.0 - Production

Related Functions

OCIErrorGet(), OCIClientVersion()

OCISvcCtxToLda()

Purpose

Toggles between a V8 or later service context handle and a V7 Lda_Def.

Syntax

sword OCISvcCtxToLda ( OCISvcCtx    *srvhp,
                       OCIError     *errhp,
                       Lda_Def      *ldap );

Parameters

svchp (IN/OUT)

The service context handle.

errhp (IN/OUT)

An error handle that you can pass to OCIErrorGet() for diagnostic information when there is an error.

ldap (IN/OUT)

A Logon Data Area for Oracle7-style OCI calls that is initialized by this call.

Comments

Toggles between an OCI release 8 or later service context handle and an Oracle7 Lda_Def.

This function can only be called after a service context has been properly initialized.

Once the service context has been translated to an Lda_Def, it can be used in release 7.x OCI calls (for example, obindps(), ofen()).

If there are multiple service contexts that share the same server handle, only one can be in Oracle7 mode at any time.

The action of this call can be reversed by passing the resulting Lda_Def to the OCILdaToSvcCtx() function.

The OCI_ATTR_IN_V8_MODE attribute of the server handle or service context handle enables an application to determine whether the application is currently in Oracle release 7 mode or Oracle release 8 or later mode.

Related Functions

OCILdaToSvcCtx()

OCIUserCallbackGet()

Purpose

Determines the callback that is registered for a handle.

Syntax

sword OCIUserCallbackGet ( void    *hndlp,
                           ub4     type,
                           void    *ehndlp,
                           ub4     fcode,
                           ub4     when,
                           OCIUserCallback (*callbackp)
                                           (
                                             void   *ctxp,
                                             void   *hndlp,
                                             ub4  type,
                                             ub4  fcode,
                                             ub1  when,
                                             sword  returnCode,
                                             ub4  *errnop,
                                             va_list arglist
                                            ),
                           void    **ctxpp,
                           OCIUcb  *ucbDesc );

Parameters

hndlp (IN)

This is the handle whose type is specified by the type parameter.

type (IN)

The handle type. The valid handle type is OCI_HTYPE_ENV. The callback is registered for all calls of the function specified by fcode made on the environment handle.

ehndlp (IN)

The OCI error or environment handle. If there is an error, it is recorded in ehndlp, and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet().

fcode (IN)

A unique function code of an OCI function. These are listed in Table 17-8.

when (IN)

Defines when the callback is invoked. Valid modes are:

• OCI_UCBTYPE_ENTRY - The callback is invoked on entry into the OCI function.

• OCI_UCBTYPE_EXIT - The callback is invoked before exit from the OCI function.

• OCI_UCBTYPE_REPLACE - If it returns anything other than an OCI_CONTINUE, then the next replacement callback and the OCI code for the OCI function are not called. Instead, processing jumps to the exit callbacks. For information about this parameter, see "OCIUserCallbackRegister()".

callbackp (OUT)

A pointer to a callback function pointer. This returns the function that is currently registered for these values of fcode, when, and hndlp. The value returned would be NULL if no callback is registered for this case.

See Also:

"OCIUserCallbackRegister()" for information about the parameters of callbackp

ctxpp (OUT)

A pointer to return context for the currently registered callback.

ucbDesc (IN)

A descriptor provided by OCI. This descriptor is passed by OCI in the environment callback. It contains the priority at which the callback would be registered. If the ucbDesc parameter is specified as NULL, then this callback has the highest priority.

User callbacks registered statically (as opposed to those registered dynamically in a package) use a NULL descriptor because they do not have a ucb descriptor to use.

Comments

This function discovers or detects what callback is registered for a particular handle.

Related Functions

OCIUserCallbackRegister()

OCIUserCallbackRegister()

Purpose

Registers a user-created callback function.

Syntax

sword OCIUserCallbackRegister ( void    *hndlp,
                                ub4      type,
                                void    *ehndlp,
                                OCIUserCallback  (callback)
                                                 (
                                                    void    *ctxp,
                                                    void    *hndlp,
                                                    ub4     type,
                                                    ub4     fcode,
                                                    ub1     when,
                                                    sword   returnCode,
                                                    ub4     *errnop,
                                                    va_list arglist
                                                  ),
                               void     *ctxp,
                               ub4      fcode,
                               ub4      when,
                               OCIUcb   *ucbDesc );

Parameters

hndlp (IN)

This is the handle whose type is specified by the type parameter.

type (IN)

The handle type. The valid handle type is OCI_HTYPE_ENV. The callback is registered for all calls of the function specified by fcode made on the environment handle.

ehndlp (IN)

The OCI error or environment handle. If there is an error, it is recorded in ehndlp and this function returns OCI_ERROR. Diagnostic information can be obtained by calling OCIErrorGet(). Because an error handle is not available within OCIEnvCallback, the environment handle is passed in as a ehndlp.

callback (IN)

A callback function pointer. The variable argument list in the OCIUserCallback function prototype are the parameters passed to the OCI function. The typedef for OCIUserCallback is described later.

If an entry callback returns anything other than OCI_CONTINUE, then the return code is passed to the subsequent entry or replacement callback, if there is one. If this is the last entry callback and there is no replacement callback, then the OCI code is executed and the return code is ignored.

If a replacement callback returns anything other than OCI_CONTINUE, then subsequent replacement callbacks and the OCI code are bypassed, and processing jumps to the exit callbacks.

If the exit callback returns anything other than OCI_CONTINUE, then that returned value is returned by the OCI function; otherwise, the return value from the OCI code or the replacement callback (if the replacement callback did not return OCI_CONTINUE and essentially bypassed the OCI code) is returned by the call.

If a NULL value is passed in for callback, then the callback is removed for the when value and the specified handle. This is the way to deregister a callback for a given ucbDesc value, including the NULL ucbDesc.

ctxp (IN)

A context pointer for the callback.

fcode (IN)

A unique function code of an OCI function. These are listed in Table 17-8.

when (IN)

Defines when the callback is invoked. Valid modes are:

• OCI_UCBTYPE_ENTRY - The callback is invoked on entry into the OCI function.

• OCI_UCBTYPE_EXIT - The callback is invoked before exit from the OCI function.

• OCI_UCBTYPE_REPLACE - If the callback returns anything other than OCI_CONTINUE, then the next replacement callback and the OCI code for the OCI function is not called. Instead, processing jumps to the exit callbacks.

ucbDesc (IN)

A descriptor provided by OCI. This descriptor is passed by OCI in the environment callback. It contains the priority at which the callback would be registered. If the ucbDesc parameter is specified as NULL, then this callback has the highest priority.

User callbacks registered statically (as opposed to those registered dynamically in a package) use a NULL descriptor as they do not have a ucb descriptor to use.

Comments

This function is used to register a user-created callback with the OCI environment.

Such callbacks allow an application to:

• Trace OCI calls for debugging and performance measurements

• Perform additional pre-processing or post-processing after selected OCI calls

• Substitute the body of a given function with proprietary code to execute on a foreign data source

The OCI supports: entry callbacks, replacement callbacks, and exit callbacks.

The three types of callbacks are identified by the modes OCI_UCBTYPE_ENTRY, OCI_UCBTYPE_REPLACE, and OCI_UCBTYPE_EXIT.

The control flow now is:

1. Execute entry callbacks.

2. Execute replacement callbacks.

3. Execute OCI code.

4. Execute exit callbacks.

Entry callbacks are executed when a program enters an OCI function.

Replacement callbacks are executed after entry callbacks. If the replacement callback returns a value of OCI_CONTINUE, then subsequent replacement callbacks or the normal OCI-specific code is executed. If the callback returns anything other than OCI_CONTINUE, then subsequent replacement callbacks and the OCI code do not execute.

After an OCI function successfully executes, or after a replacement callback returns something other than OCI_CONTINUE, program control transfers to the exit callback (if one is registered).

If a replacement or exit callback returns anything other than OCI_CONTINUE, then the return code from the callback is returned from the associated OCI call.

To determine the callback that is registered for the handle, you can use OCIUserCallbackGet().

The prototype of the OCIUserCallback typedef is:

typedef sword (*OCIUserCallback)
           (void    *ctxp,
            void    *hndlp,
            ub4     type,
            ub4     fcode,
            ub4     when,
            sword   returnCode,
            sb4     *errnop,
            va_list arglist );

The parameters to the OCIUserCallback function prototype are:

ctxp (IN)

The context passed in as ctxp in the register callback function.

hndlp (IN)

This is the handle whose type is specified in the type parameter. It is the handle on which the callback is invoked. Because only a type of OCI_HTYPE_ENV is allowed, the environment handle, env, would be passed in here.

type (IN)

The type registered for the hndlp. The valid handle type is OCI_HTYPE_ENV. The callback is registered for all calls of the function specified by fcode made on the environment handle.

fcode (IN)

The function code of the OCI call. These are listed in Table 17-8. Note that callbacks can be registered for only the OCI calls listed in Table 17-3.

when (IN)

The when value of the callback.

returnCode (IN)

This is the return code from the previous callback or the OCI code. For the first entry callback, OCI_SUCCESS is always passed in. For the subsequent callbacks, the return code from the OCI code or the previous callback is passed in.

errnop (IN/OUT)

When the first entry callback is called, the input value of *errnop is 0. If the callback is returning any value other than OCI_CONTINUE, then it must also set an error number in *errnop. This value is the set in the error handle passed in the OCI call.

For all subsequent callbacks, the input value of *errnop is the value of error number in the error handle. Therefore, if the previous callback did not return OCI_CONTINUE, then the out value of *errnop from the previous callback would be the one in the error handle, and that value would be passed in here to the subsequent callback. If, however, the previous callback returned OCI_CONTINUE, then whatever value is in the error handle would be passed in here.

Note that if a non-Oracle error number is returned in *errnop, then a callback must also be registered for the OCIErrorGet() function to return appropriate text for the error number.

arglist (IN)

These are the parameters to the OCI call passed in here as variable number of arguments. They should be dereferenced using va_arg, as illustrated in the user callback demonstration programs.

See Also:

Appendix B, "OCI Demonstration Programs"

Table 17-8 and Table 17-9 list the OCI Function codes and provides the OCI routine name and its function number.

Related Functions

OCIUserCallbackGet()