The mi_file_errno() function
The mi_file_errno() function returns the value of the system errno variable after a file input/output (I/O) operation. This value is the last errno value generated during an mi_file* function call and comes from the computer where the file is located. This function does not translate the value from one platform to another.
Syntax
mi_integer mi_file_errno()| Valid in client LIBMI application? | Valid in user-defined routine? |
|---|---|
| Yes | Yes |
Usage
File I/O functions of the C library call underlying system or platform file I/O functions. These system or platform functions set a global variable called errno to indicate status. For a list of DataBlade® API file-access functions, see the Informix® DataBlade® API Programmer's Guide.
These file-access functions call the corresponding C library functions to perform their tasks. Therefore, the value of the errno is available for a DataBlade® API module.
On UNIX™ or Linux™, you can check the errno variable directly, immediately after a DataBlade® API file I/O function. Therefore, use of mi_file_errno() is not required for UNIX™ or Linux™. In fact, the mi_file_errno() function on UNIX™ or Linux™ is the same as the errno variable.
If you plan to port a user-defined routine (UDR) or DataBlade® module to Windows™, it is strongly recommended that you use the mi_file_errno() to retrieve the errno value.
On Windows™, global variables, such as errno, are not easily accessible. Therefore, to obtain the errno value after a DataBlade® API file I/O operation, use the mi_file_errno() function. DataBlade® APIs and UDRs that execute on the Windows™ platform must use mi_file_errno() to access the errno for file operations.
Return values
None.