C interfaces are provided for the ECI and ESI for building 32-bit applications that can be run in local mode. Separate C interfaces are provided for the ECI and ESI for building 32-bit or 64-bit applications that can be run in remote mode.
A user application must only use a single process to make API requests. However, in environments in which a process can generate several threads, the user application can be multithreaded and each thread can make API requests. On UNIX and Linux, a child process, started from a parent application that has already made a Client API request, cannot make subsequent Client API requests. A child process that makes Client API requests must be started before the parent application has made any Client API requests.
For remote mode, a C interface is provided for the ECI and ESI. For more information see Making ECI V2 and ESI V2 calls from C programs.