This place is most things about SAP.
It's DAVID's knowledge base to summarize his knowledge of SAP during work.
If you also wanna build it to share your knowledge togerther with me here, please just mail blueoxygen at gmail.com.

Other

• G_GET_USER_PARAMETER

Get user's parameter

RFC

• RFC_PING

check RFC destination

• OWN_LOGICAL_SYSTEM_GET

Specify Name of Current Logged-on System (client in R/3 System)

• RFC_READ_TABLE

External access to R/3 tables via RFC

Database

• ENQUEUE_E_TABLE

Lock the specified table

• DEQUEUE_E_TABLE

Unlock the spefified table

• DEQUEUE_ALL

Release Locks of an LUW

• DP_GET_FIELDS_FROM_TABLE

Get DDIC table's information

• GET_COMPONENT_LIST

Get user defined type's information

• GET_FIELDTAB

Read fields of a table in the format DFIES

• DDIF_FIELDINFO_GET

Interface to read text on tables or types


Variant

• VARI_USER_VARS_GET

Reads existing variable values

• VARI_USER_VARS_SET

Changes existing variable values

• VARI_USER_VARS_COPY

Copies variable values

• VARI_USER_VARS_DELETE

Deletes variable values

• VARI_USER_VARS_RENAME

Renames variable values

• VARI_USER_VARS_DIALOG

Dialog for entering variable values

• RS_VARIANT_VALUES_TECH_DATA

Get variant data

• RS_CHANGE_CREATED_VARIANT

Change variant data



Spool

• RSPO_RETURN_ABAP_SPOOLJOB

Return the Spool' content by spefified spool no(sy-sy-spono)

• RSPO_RETURN_SPOOLJOB

Return the spool content

• RSPO_R_RDELETE_SPOOLREQ

Delete the spool content by spool id

• GET_PRINT_PARAMETERS

Read, determine, change spool print parameters and archive parameters

Currency

• CURRENCY_AMOUNT_DISPLAY_TO_SAP
• CURRENCY_AMOUNT_SAP_TO_DISPLAY
• FWOS_CURRENCY_DECIMALS_READ
• CONVERT_TO_FOREIGN_CURRENCY
• CONVERT_TO_LOCAL_CURRENCY

Sample codes link