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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.
What is HCL OneDB™ ESQL/C?
HCL OneDB™ ESQL/C data typesThese topics contain information about the correspondence between SQL and C data types and how to handle data types in the program.
Data-type alignment library functions

Data-type alignment library functions

The following library functions provide machine-independent size and alignment information for different data types and help you work with null database values.


Function name	Description	See
risnull()	Checks whether a C variable is null	The risnull() function
rsetnull()	Sets a C variable to null	The rsetnull() function
rtypalign()	Aligns data on correct type boundaries	The rtypalign() function
rtypmsize()	Gives the byte size of SQL data types	The rtypmsize() function
rtypname()	Returns the name of a specified SQL data type	The rtypname() function
rtypwidth()	Returns the minimum number of characters that a character data type needs to avoid truncation	The rtypwidth() function

When you compile your program with the esql command, esql calls on the linker to link these functions to your program.