O/S Interoperability Commands

mvBASIC enables the user to execute Windows programs and/or to access files using the O/S interoperability commands described in this section. While this section describes new mvBASIC keywords and functionality, the actual functioning occurs at the Windows O/S level, which imposes its own rules and constraints, such as:

UOPEN and UCREATE return a Windows file-handle. These are a limited resource and must be released explicitly.
The variable returned by UEXECUTE and used by UWAITFOR or UMESSAGE is also a Windows file-handle. Changing it and then feeding the result to UMESSAGE or UWAITFOR could cause unpredictable results.

Command	Description
UCLOSE Command	Closes a file variable previously opened with the UOPEN command.
UCREATE Command	Creates and opens a specified file on the host system.
UDELETE Command	Removes the directory entry named by the path name.
UERROR Function	Returns the error number that resulted from the previous Inter-Operating System command.
UEXECUTE Command	Allows users to execute various Windows programs from within mvBASIC.
ULOCK Command	Locks or unlocks a file specified by a file variable.
LSEEK Function	Moves the file pointer in an open file and returns the position of the file pointer.
UMESSAGE Command	Sends a Windows-style message to the mvBase client linked to the process executing the command.
UOPEN Command	Opens a given file name to an mvBASIC file variable
READ Command	Reads data from a previously opened file on the host system.
SYSTEM Function	Obtains information from the underlying operating system environment.
UWAITFOR Command	Causes the process to wait until the Windows application.
UWRITE Command	Writes data to a previously opened file on the host system.