swap.h
Swaps spawned program with calling program.- swap_clearkeyboardon, swap_clearkeyboardoff
- swap_freeparagraphs
- swap_freeparagraphson, swap_freeparagraphsoff
- swap_isclearkeyboardon, swap_isfreeparagraphson, swap_ison, swap_ispipeon, swap_istempcheckon, swap_istrapcbreakon swap_iswindowon
- swap_on, swap_off
- swap_pipe
- swap_pipeon, swap_pipeoff
- swap_tempcheckon, swap_tempcheckoff
- swap_trapcbreakon, swap_trapcbreakoff
- swap_window
- swap_windowon, swap_windowoff
swap_clearkeyboardon, swap_clearkeyboardoff
- Header
- swap.h
- Prototype
-
void swap_clearkeyboardon(void);
void swap_clearkeyboardoff(void); - Description
- These functions turn on or off the clear keyboard buffer feature. When on, the keyboard buffer is cleared before returning from a spawned process. The default is on. These functions can be nested. If two calls are made to the off function, two calls must also be made to the on function in order to reactivate the keyboard feature.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off
swap_freeparagraphs
- Header
- swap.h
- Prototype
- void swap_freeparagraphs(unsigned int para);
- Description
-
This function specifies the number of 16-byte paragraphs of memory
that will be made available for the spawned process. The argument
para is the number of 16 byte paragraphs of memory to make
available for the spawned process. The swap facility normally frees
all the memory it can, but if you are running a program that will only
require only a small amount of memory then the use of the
swap_freeparagraphs function will allow the swap to execute
faster. Each kilobyte of memory consists of 64 paragraphs.
Calling swap_freeparagraphs implicitly turns on the free paragraphs feature. A call to swap_freeparagraphsoff turns it off again. If the number of paragraphs specified is greater than can be freed, the swap facility frees all it can and continues to spawn the process.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off swap_freeparagraphson swap_freeparagraphsoff
swap_freeparagraphson, swap_freeparagraphsoff
- Header
- swap.h
- Prototype
-
void swap_freeparagraphson(void);
void swap_freeparagraphsoff(void); - Description
-
These functions turn on or off the "free paragraph" feature. When
on, swap frees only the specified amount of memory during the
spawning of a child process. The number of paragraphs to be freed
must be specified first by a call to swap_freeparagraphs. This
call automatically turns on the free paragraph feature, without
needing a call to swap_freeparagraphson. To turn it off, use
swap_freeparagraphsoff.
Calls to the off and on functions can be nested. If two calls are made to the off function, two calls must also be made to the on function to reactivate the feature.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off swap_freeparagraphs
swap_isclearkeyboardon, swap_isfreeparagraphson, swap_ison, swap_ispipeon, swap_istempcheckon, swap_istrapcbreakon swap_iswindowon
- Header
- swap.h
- Prototype
-
int swap_isclearkeyboardon(void);
int swap_isfreeparagraphson(void);
int swap_ison(void);
int swap_ispipeon(void);
int swap_istempcheckon(void);
int swap_istrapcbreakon(void);
int swap_iswindowon(void); - Description
- These functions return the flag status of the configurable features of the swap_functions. See the descriptions of the corresponding control functions for more information.
- Return Value
- A non-zero, positive return value indicates the feature is turned on.
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off
swap_on, swap_off
- Header
- swap.h
- Prototype
-
void swap_on(void);
void swap_off(void); - Description
- These functions turn swapping on or off. When off, calls to spawn and system behave as normal. The default is on. Function calls can be nested; if two calls are made to the off function, two calls must be made to the on function to reactivate swapping. swap_functions are for use only in real mode MS-DOS. They support the C (compact), L (Large), and V (Virtual) memory models. To use these functions, link the appropriate object file with your program. Object files are _swapc. obj, _swapl. obj, and _swapv. obj respectively.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
swap_pipe
- Header
- swap.h
- Prototype
- void swap_pipe(const char *file);
- Description
- This function copies the output from a spawned program and redirects it to a file. The output must be stdout or stderr. Calling swap_pipeoff suspends output to the pipe file. The swap_pipe function can be use simultaneously with swap_window.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off swap_pipeon swap_pipeoff
swap_pipeon, swap_pipeoff
- Header
- swap.h
- Prototype
-
void swap_pipeon(void);
void swap_pipeoff(void); - Description
-
These functions turn on or off piping output to a file. When on, all
output from the spawned program that goes through stdout or
stderr is piped to the pipe file. A pipe file must be specified by
calling swap_pipe, which automatically turns on piping. To turn off
automatic piping, invoke swap_pipeoff. To turn it back on again,
call swap_pipeon.
Calls can be nested. If two calls are made to the off function, two calls must be made to the on function to reactivate the pipe.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off
swap_tempcheckon, swap_tempcheckoff
- Header
- swap.h
- Prototype
-
void swap_tempcheckon(void);
void swap_tempcheckoff(void); - Description
-
These functions determine where the memory image file is saved
when a program is spawned. By default the swap facility saves its
memory image file in the directory pointed to by the TEMP or TMP
environment variable if there is one, or in the current working
directory if there is not. If this behavior is turned off, the swap file is always stored in the
current working directory.
The ability to disable checking of TEMP or TMP is useful when the environment variable points to a RAM disk or other specialized memory that you do not want used for the memory image of the program being swapped.
Calls to swap_tempcheckon and swap_tempcheckoff can be nested. If two calls are made to the off function, two calls must be made to the on function to reactivate checking of TEMP or TMP.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off
swap_trapcbreakon, swap_trapcbreakoff
- Header
- swap.h
- Prototype
-
void swap_trapcbreakon(void);
void swap_trapcbreakoff(void); - Description
- These functions turn on or off control-c trapping when a program is spawned. When on, control-c and control-break are trapped by the swap facility and ignored. The default is on. If you want a spawned program to react to control-c or control-break, you install a control-c handler using the controlc_functions, and then turn off the swap facility by calling swap_trapcbreakoff.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off controlc_open
swap_window
- Header
- swap.h
- Prototype
- void swap_window(int col, int lin, int x, int y);
- Description
-
This function receives output sent by stdout or stderr from a
spawned program and displays the output on the screen in a
specified window area. The window area dimensions are:
Output to the window is scrolled and wrapped appropriately. Calling swap_windowoff suspends output.col The left column of the window lin The top line of the window x The width of the window in columns y The depth of the window in rows - Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off swap_windowon swap_windowoff
swap_windowon, swap_windowoff
- Header
- swap.h
- Prototype
-
void swap_windowon(void);
void swap_windowoff(void); - Description
-
These functions turn on or off the window program output for
spawned programs. When on, all output from the program that goes
through stdout or stderr is sent to a specified screen area
(window). The window must be defined first by calling
swap_window, in which case swap_windowon is only required if
a previous call has been made to swap_windowoff.
Calls to swap_windowoff and swap_windowon can be nested. If two calls are made to the off function, two calls must be made to the on function to reactivate the feature.
- Return Value
- None
- Compatibility
- DOS Large and Compact memory models only.
- See Also
- swap_on swap_off swap_window