Terminal Information

External Development Guide: IDL Internals: Miscellaneous

Terminal Information

The global variable IDL_FileTerm is a structure of type IDL_TERMINFO:

typedef struct {  
  char *name;     /* Name Of Terminal Type */  
  char is_tty;    /* True if stdin is a terminal */  
  int lines;      /* Lines on screen */  
  int columns;    /* Width of output */  
} IDL_TERMINFO;

Note
Under operating systems that do not support the concept of a terminal (Microsoft Windows) the name and is_tty fields are not present.

IDL_FileTerm is initialized when IDL is started. Few, if any, user routines will need this information, because user routines should not do their own I/O. User routines that must do their own I/O should use this variable instead of making assumptions about the output device.

Note
Under Microsoft Windows, the IDL_FileTerm is not accessible outside of the IDL sharable library, and cannot be directly accessed by user code. Instead, use the functions described in the following section.

Functions for Returning IDL_FileTerm Variable Values

The following functions can be used to return values from the IDL_FileTerm variable. They return the same information contained in the global variable, but in a functional form. This is the preferred way to access the IDL_FileTerm information, as it will work on any platform.

char *IDL_FileTermName(void)

This function returns the value of IDL_FileTerm.name. This function is only available under UNIX.

int IDL_FileTermIsTty(void)

This function returns the value of IDL_FileTerm.is_tty. This function is only available under UNIX.

int IDL_FileTermLines(void)

This function returns the value of IDL_FileTerm.lines.

int IDL_FileTermColumns(void)

This function returns the value of IDL_FileTerm.columns.

IDL Online Help (March 06, 2007)