Functionality
This function module checks all authorizations as at the start of atransaction, that is, the authorization object S_TCODE and authorizationobjects that were stored when defining the transaction using SE93. Itshould be called before a CALL TRANSACTION, since CALL TRANSACTION can,by default, only perform these authorization checks if this is definedin table TCDCOUPLES by SE97.
CALL FUNCTION 'AUTHORITY_CHECK_TCODE
EXPORTING 'SM51'
EXCEPTIONS OK = 1
NOT_OK = 2.

Notes
The table evaluated by the kernel, TCDCOUPLES, is also taken intoaccount by this function module. At Call Transaction, whether the kernelcheck is performed for the transaction code of the called transactiondepends on profile parameter auth/check/calltransaction (default = 2)and the table TCDCOUPLES:
auth/check/calltransaction | 0 1 2 3
--------------------------------------------
tcdcouples-okflag = X | n j j j
tcdcouples-okflag = N | n j n n
tcdcouples-okflag = ' ' | n j n j
No record in tcdcouples | n j n j
The function modules behaves differently in each case (call in thecalling transaction, call in the called transaction).
Call before Call Transaction (tcode <> sy-tcode):
auth/check/calltransaction | 0 1 2 3
--------------------------------------------
tcdcouples-okflag = X | n j j j
tcdcouples-okflag = N | n j n n
tcdcouples-okflag = ' ' | n j j j
No record in tcdcouples | n j j j
Although there may be a double check here, this is nevertheless usefulsince the application in ABAP can react better to the result of thefunction module than the kernel.
Call in Call Transaction (tcode = sy-tcode):
auth/check/calltransaction | 0 1 2 3
--------------------------------------------
tcdcouples-okflag = X | n j j j
tcdcouples-okflag = N | n j n n
tcdcouples-okflag = ' ' | n j n n
No record in tcdcouples | n j n n
Since this check has been performed by the kernel since SAP R/3 4.6C, itis deactivated here by default and must explicitly be activated for eachtrnasaction by an entry in table TCDCOUPLES (transaction SE97) withtcode = called and okflag = X.