Each Tamino API for C function except tac_init() returns an integer value.

Upon success, this value is the predefined constant TAC_SUCCESS, which is defined as 0 in the header file TaminoAPI4C.h.

If a function call fails, an error code is returned. A negative value indicates that the API already detected an error without communicating with Tamino. An error code between 100 and 999 indicates a communication problem, see HTTP Status Codes for more details. An error code greater than 999 indicates a processing problem in the Tamino XML Server; more details can be obtained by calling the function tac_get_messagetext().