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Client APIs and toolsYou can use the HCL OneDB™ implementation of client APIs to develop applications for HCL OneDB™ database servers.
ESQL/C GuideThe HCL OneDB™ ESQL/C Programmer's Manual explains how to use , the HCL OneDB™ implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
Database server communication
HCL OneDB™ librariesThese topics describe how to link the static, shared, and thread-safe HCL OneDB™ general libraries with your application.
Create thread-safe ESQL/C applications
Program a thread-safe ESQL/C applicationThis section provides useful hints for how to create thread-safe applications.
Message file descriptors

Message file descriptors

By default ESQL/C frees all file descriptors for a message file when it closes the message file. As a performance optimization, however, you can set the environment variable IFX_FREE_FD to cause to not free the file descriptor if the message file being closed is open for another thread. If you set IFX_FREE_FD to 1, frees the message file descriptor only for the thread that closes the file.