* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: scr_dump.5,v 1.9 2017/04/22 18:44:25 tom Exp @
+ * @Id: scr_dump.5,v 1.10 2017/04/29 20:53:55 tom Exp @
-->
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<H1 class="no-header">scr_dump 5</H1>
<PRE>
-<STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG> <STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>
+<STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>
<STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- The curses library provides applications with the ability
- to write the contents of a window to an external file
- using <STRONG>scr_dump</STRONG> or <STRONG>putwin</STRONG>, and read it back using
- <STRONG>scr_restore</STRONG> or <STRONG>getwin</STRONG>.
+ The curses library provides applications with the ability to write the
+ contents of a window to an external file using <STRONG>scr_dump</STRONG> or <STRONG>putwin</STRONG>, and
+ read it back using <STRONG>scr_restore</STRONG> or <STRONG>getwin</STRONG>.
- The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions do the work; while
- <STRONG>scr_dump</STRONG> and <STRONG>scr_restore</STRONG> conveniently save and restore the
- whole screen, i.e., <STRONG>stdscr</STRONG>.
+ The <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG> functions do the work; while <STRONG>scr_dump</STRONG> and
+ <STRONG>scr_restore</STRONG> conveniently save and restore the whole screen, i.e., <STRONG>std-</STRONG>
+ <STRONG>scr</STRONG>.
</PRE><H3><a name="h3-ncurses6">ncurses6</a></H3><PRE>
- A longstanding implementation of screen-dump was revised
- with ncurses6 to remedy problems with the earlier
- approach:
+ A longstanding implementation of screen-dump was revised with ncurses6
+ to remedy problems with the earlier approach:
- <STRONG>o</STRONG> A "magic number" is written to the beginning of the
- dump file, allowing applications (such as <STRONG>file(1)</STRONG>) to
- recognize curses dump files.
+ <STRONG>o</STRONG> A "magic number" is written to the beginning of the dump file,
+ allowing applications (such as <STRONG>file(1)</STRONG>) to recognize curses dump
+ files.
- Because ncurses6 uses a new format, that requires a
- new magic number was unused by other applications.
- This 16-bit number was unused:
+ Because ncurses6 uses a new format, that requires a new magic num-
+ ber was unused by other applications. This 16-bit number was
+ unused:
0x8888 (octal "\210\210")
0x88888888 (octal "\210\210\210\210")
- This is the pattern submitted to the maintainers of
- the <STRONG>file</STRONG> program:
+ This is the pattern submitted to the maintainers of the <STRONG>file</STRONG> pro-
+ gram:
#
# ncurses5 (and before) did not use a magic number,
0 string \210\210\210\210ncurses ncurses6 screen image
#
- <STRONG>o</STRONG> The screen dumps are written in textual form, so that
- internal data sizes are not directly related to the
- dump-format, and enabling the library to read dumps
- from either narrow- or wide-character- configurations.
+ <STRONG>o</STRONG> The screen dumps are written in textual form, so that internal data
+ sizes are not directly related to the dump-format, and enabling the
+ library to read dumps from either narrow- or wide-character- con-
+ figurations.
- The <EM>narrow</EM> library configuration holds characters and
- video attributes in a 32-bit <STRONG>chtype</STRONG>, while the <EM>wide-</EM>
- <EM>character</EM> library stores this information in the
- <STRONG>cchar_t</STRONG> structure, which is much larger than 32-bits.
+ The <EM>narrow</EM> library configuration holds characters and video
+ attributes in a 32-bit <STRONG>chtype</STRONG>, while the <EM>wide-character</EM> library
+ stores this information in the <STRONG>cchar_t</STRONG> structure, which is much
+ larger than 32-bits.
- <STRONG>o</STRONG> It is possible to read a screen dump into a terminal
- with a different screen-size, because the library
- truncates or fills the screen as necessary.
+ <STRONG>o</STRONG> It is possible to read a screen dump into a terminal with a differ-
+ ent screen-size, because the library truncates or fills the screen
+ as necessary.
- <STRONG>o</STRONG> The ncurses6 <STRONG>getwin</STRONG> reads the legacy screen dumps from
- ncurses5.
+ <STRONG>o</STRONG> The ncurses6 <STRONG>getwin</STRONG> reads the legacy screen dumps from ncurses5.
</PRE><H3><a name="h3-ncurses5-_legacy_">ncurses5 (legacy)</a></H3><PRE>
- The screen-dump feature was added to ncurses in June 1995.
- While there were fixes and improvements in succeeding
- years, the basic scheme was unchanged:
+ The screen-dump feature was added to ncurses in June 1995. While there
+ were fixes and improvements in succeeding years, the basic scheme was
+ unchanged:
<STRONG>o</STRONG> The <STRONG>WINDOW</STRONG> structure was written in binary form.
- <STRONG>o</STRONG> The <STRONG>WINDOW</STRONG> structure refers to lines of data, which
- were written as an array of binary data following the
- <STRONG>WINDOW</STRONG>.
+ <STRONG>o</STRONG> The <STRONG>WINDOW</STRONG> structure refers to lines of data, which were written as
+ an array of binary data following the <STRONG>WINDOW</STRONG>.
- <STRONG>o</STRONG> When <STRONG>getwin</STRONG> restored the window, it would keep track
- of offsets into the array of line-data and adjust the
- <STRONG>WINDOW</STRONG> structure which was read back into memory.
+ <STRONG>o</STRONG> When <STRONG>getwin</STRONG> restored the window, it would keep track of offsets
+ into the array of line-data and adjust the <STRONG>WINDOW</STRONG> structure which
+ was read back into memory.
- This is similar to Unix SystemV, but does not write a
- "magic number" to identify the file format.
+ This is similar to Unix SystemV, but does not write a "magic number" to
+ identify the file format.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- There is no standard format for <STRONG>putwin</STRONG>. This section
- gives a brief description of the existing formats.
+ There is no standard format for <STRONG>putwin</STRONG>. This section gives a brief
+ description of the existing formats.
</PRE><H3><a name="h3-X_Open-Curses">X/Open Curses</a></H3><PRE>
X/Open's documentation for <EM>enhanced</EM> <EM>curses</EM> says only:
- The <EM>getwin(</EM> <EM>)</EM> function reads window-related data stored
- in the file by <EM>putwin(</EM> <EM>)</EM>. The function then creates
- and initializes a new window using that data.
+ The <EM>getwin(</EM> <EM>)</EM> function reads window-related data stored in the file
+ by <EM>putwin(</EM> <EM>)</EM>. The function then creates and initializes a new win-
+ dow using that data.
- The <EM>putwin(</EM> <EM>)</EM> function writes all data associated with
- <EM>win</EM> into the <EM>stdio</EM> stream to which <EM>filep</EM> points, using
- an <STRONG>unspecified</STRONG> <STRONG>format</STRONG>. This information can be
- retrieved later using <EM>getwin(</EM> <EM>)</EM>.
+ The <EM>putwin(</EM> <EM>)</EM> function writes all data associated with <EM>win</EM> into the
+ <EM>stdio</EM> stream to which <EM>filep</EM> points, using an <STRONG>unspecified</STRONG> <STRONG>format</STRONG>.
+ This information can be retrieved later using <EM>getwin(</EM> <EM>)</EM>.
- In the mid-1990s when the X/Open Curses document was writ-
- ten, there were still systems using older, less capable
- curses libraries (aside from the BSD curses library which
- was not relevant to X/Open because it did not meet the
- criteria for <EM>base</EM> <EM>curses</EM>). The document explained the
+ In the mid-1990s when the X/Open Curses document was written, there
+ were still systems using older, less capable curses libraries (aside
+ from the BSD curses library which was not relevant to X/Open because it
+ did not meet the criteria for <EM>base</EM> <EM>curses</EM>). The document explained the
term "enhanced" as follows:
- <STRONG>o</STRONG> Shading is used to identify <EM>X/Open</EM> <EM>Enhanced</EM> <EM>Curses</EM>
- material, relating to interfaces included to pro-
- vide enhanced capabilities for applications origi-
- nally written to be compiled on systems based on
- the UNIX operating system. Therefore, the features
- described may not be present on systems that con-
- form to <STRONG>XPG4</STRONG> <STRONG>or</STRONG> <STRONG>to</STRONG> <STRONG>earlier</STRONG> <STRONG>XPG</STRONG> <STRONG>releases</STRONG>. The rele-
- vant reference pages may provide additional or more
- specific portability warnings about use of the
- material.
+ <STRONG>o</STRONG> Shading is used to identify <EM>X/Open</EM> <EM>Enhanced</EM> <EM>Curses</EM> material,
+ relating to interfaces included to provide enhanced capabilities
+ for applications originally written to be compiled on systems
+ based on the UNIX operating system. Therefore, the features
+ described may not be present on systems that conform to <STRONG>XPG4</STRONG> <STRONG>or</STRONG>
+ <STRONG>to</STRONG> <STRONG>earlier</STRONG> <STRONG>XPG</STRONG> <STRONG>releases</STRONG>. The relevant reference pages may pro-
+ vide additional or more specific portability warnings about use
+ of the material.
- In the foregoing, emphasis was added to <STRONG>unspecified</STRONG> <STRONG>format</STRONG>
- and to <STRONG>XPG4</STRONG> <STRONG>or</STRONG> <STRONG>to</STRONG> <STRONG>earlier</STRONG> <STRONG>XPG</STRONG> <STRONG>releases</STRONG>, for clarity.
+ In the foregoing, emphasis was added to <STRONG>unspecified</STRONG> <STRONG>format</STRONG> and to <STRONG>XPG4</STRONG>
+ <STRONG>or</STRONG> <STRONG>to</STRONG> <STRONG>earlier</STRONG> <STRONG>XPG</STRONG> <STRONG>releases</STRONG>, for clarity.
</PRE><H3><a name="h3-Unix-SystemV">Unix SystemV</a></H3><PRE>
- Unix SystemV curses identified the file format by writing
- a "magic number" at the beginning of the dump. The <STRONG>WINDOW</STRONG>
- data and the lines of text follow, all in binary form.
+ Unix SystemV curses identified the file format by writing a "magic num-
+ ber" at the beginning of the dump. The <STRONG>WINDOW</STRONG> data and the lines of
+ text follow, all in binary form.
The Solaris curses source has these definitions:
#define SVR2_DUMP_MAGIC_NUMBER 0433
#define SVR3_DUMP_MAGIC_NUMBER 0434
- That is, the feature was likely introduced in SVr2 (1984),
- and improved in SVr3 (1987). The Solaris curses source
- has no magic number for SVr4 (1989). Other operating sys-
- tems (AIX and HPUX) use a magic number which would corre-
- spond to this definition:
+ That is, the feature was likely introduced in SVr2 (1984), and improved
+ in SVr3 (1987). The Solaris curses source has no magic number for SVr4
+ (1989). Other operating systems (AIX and HPUX) use a magic number
+ which would correspond to this definition:
/* curses screen dump magic number */
#define SVR4_DUMP_MAGIC_NUMBER 0435
- That octal number in bytes is 001, 035. Because most Unix
- vendors use big-endian hardware, the magic number is writ-
- ten with the high-order byte first, e.g.,
+ That octal number in bytes is 001, 035. Because most Unix vendors use
+ big-endian hardware, the magic number is written with the high-order
+ byte first, e.g.,
01 35
- After the magic number, the <STRONG>WINDOW</STRONG> structure and line-data
- are written in binary format. While the magic number used
- by the Unix systems can be seen using <STRONG>od(1)</STRONG>, none of the
- Unix systems documents the format used for screen-dumps.
+ After the magic number, the <STRONG>WINDOW</STRONG> structure and line-data are written
+ in binary format. While the magic number used by the Unix systems can
+ be seen using <STRONG>od(1)</STRONG>, none of the Unix systems documents the format used
+ for screen-dumps.
- The Unix systems do not use identical formats. While col-
- lecting information for for this manual page, the <EM>save-</EM>
- <EM>screen</EM> test-program produced dumps of different size (all
- on 64-bit hardware, on 40x80 screens):
+ The Unix systems do not use identical formats. While collecting infor-
+ mation for for this manual page, the <EM>savescreen</EM> test-program produced
+ dumps of different size (all on 64-bit hardware, on 40x80 screens):
<STRONG>o</STRONG> AIX (51817 bytes)
</PRE><H3><a name="h3-Solaris">Solaris</a></H3><PRE>
- As noted above, Solaris curses has no magic number corre-
- sponding to SVr4 curses. This is odd since Solaris was
- the first operating system to pass the SVr4 guidelines.
- Solaris has two versions of curses:
+ As noted above, Solaris curses has no magic number corresponding to
+ SVr4 curses. This is odd since Solaris was the first operating system
+ to pass the SVr4 guidelines. Solaris has two versions of curses:
<STRONG>o</STRONG> The default curses library uses the SVr3 magic number.
- <STRONG>o</STRONG> There is an alternate curses library in <STRONG>/usr/xpg4</STRONG>.
- This uses a textual format with no magic number.
+ <STRONG>o</STRONG> There is an alternate curses library in <STRONG>/usr/xpg4</STRONG>. This uses a
+ textual format with no magic number.
- According to the copyright notice, the <EM>xpg4</EM> Solaris
- curses library was developed by MKS (Mortice Kern Sys-
- tems) from 1990 to 1995.
+ According to the copyright notice, the <EM>xpg4</EM> Solaris curses library
+ was developed by MKS (Mortice Kern Systems) from 1990 to 1995.
- Like ncurses6, there is a file-header with parameters.
- Unlike ncurses6, the contents of the window are writ-
- ten piecemeal, with coordinates and attributes for
- each chunk of text rather than writing the whole win-
- dow from top to bottom.
+ Like ncurses6, there is a file-header with parameters. Unlike
+ ncurses6, the contents of the window are written piecemeal, with
+ coordinates and attributes for each chunk of text rather than writ-
+ ing the whole window from top to bottom.
</PRE><H3><a name="h3-PDCurses">PDCurses</a></H3><PRE>
- PDCurses added support for screen dumps in version 2.7
- (2005). Like Unix SystemV and ncurses5, it writes the
- <STRONG>WINDOW</STRONG> structure in binary, but begins the file with its
- three-byte identifier "PDC", followed by a one-byte ver-
- sion, e.g.,
+ PDCurses added support for screen dumps in version 2.7 (2005). Like
+ Unix SystemV and ncurses5, it writes the <STRONG>WINDOW</STRONG> structure in binary,
+ but begins the file with its three-byte identifier "PDC", followed by a
+ one-byte version, e.g.,
"PDC\001"
</PRE><H3><a name="h3-NetBSD">NetBSD</a></H3><PRE>
- As of April 2017, NetBSD curses does not yet support
- screen dumps.
+ As of April 2017, NetBSD curses does not support <STRONG>scr_dump</STRONG> and
+ <STRONG>scr_restore</STRONG> (or <STRONG>scr_init</STRONG>, <STRONG>scr_set</STRONG>), although it has <STRONG>putwin</STRONG> and <STRONG>getwin</STRONG>.
+
+ Like ncurses5, NetBSD <STRONG>putwin</STRONG> does not identify its dumps with a useful
+ magic number. It writes
+
+ <STRONG>o</STRONG> the curses shared library major and minor versions as the first two
+ bytes (e.g., 7 and 1),
+
+ <STRONG>o</STRONG> followed by a binary dump of the <STRONG>WINDOW</STRONG>,
+
+ <STRONG>o</STRONG> some data for wide-characters referenced by the <STRONG>WINDOW</STRONG> structure,
+ and
+
+ <STRONG>o</STRONG> finally, lines as done by other implementations.
</PRE><H2><a name="h2-EXAMPLE">EXAMPLE</a></H2><PRE>
- Given a simple program which writes text to the screen
- (and for the sake of example, limiting the screen-size to
- 10x20):
+ Given a simple program which writes text to the screen (and for the
+ sake of example, limiting the screen-size to 10x20):
#include <curses.h>
9:\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s
10:\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s\s
- The first four octal escapes are actually nonprinting
- characters, while the remainder of the file is printable
- text. You may notice:
+ The first four octal escapes are actually nonprinting characters, while
+ the remainder of the file is printable text. You may notice:
- <STRONG>o</STRONG> The actual color pair values are not written to the
- file.
+ <STRONG>o</STRONG> The actual color pair values are not written to the file.
- <STRONG>o</STRONG> All characters are shown in printable form; spaces are
- "\s" to ensure they are not overlooked.
+ <STRONG>o</STRONG> All characters are shown in printable form; spaces are "\s" to
+ ensure they are not overlooked.
- <STRONG>o</STRONG> Attributes are written in escaped curly braces, e.g.,
- "\{BOLD}", and may include a color-pair (C1 or C2 in
- this example).
+ <STRONG>o</STRONG> Attributes are written in escaped curly braces, e.g., "\{BOLD}",
+ and may include a color-pair (C1 or C2 in this example).
- <STRONG>o</STRONG> The parameters in the header are written out only if
- they are nonzero. When reading back, order does not
- matter.
+ <STRONG>o</STRONG> The parameters in the header are written out only if they are
+ nonzero. When reading back, order does not matter.
- Running the same program with Solaris <EM>xpg4</EM> curses gives
- this dump:
+ Running the same program with Solaris <EM>xpg4</EM> curses gives this dump:
MAX=10,20
BEG=0,0
9,19,0,0,
CUR=11,5
- Solaris <STRONG>getwin</STRONG> requires that all parameters are present,
- and in the same order. The <EM>xpg4</EM> curses library does not
- know about the <STRONG>bce</STRONG> (back color erase) capability, and does
- not color the window background.
+ Solaris <STRONG>getwin</STRONG> requires that all parameters are present, and in the
+ same order. The <EM>xpg4</EM> curses library does not know about the <STRONG>bce</STRONG> (back
+ color erase) capability, and does not color the window background.
- On the other hand, the SVr4 curses library does know about
- the background color. However, its screen dumps are in
- binary. Here is the corresponding dump (using "od -t
- x1"):
+ On the other hand, the SVr4 curses library does know about the back-
+ ground color. However, its screen dumps are in binary. Here is the
+ corresponding dump (using "od -t x1"):
0000000 1c 01 c3 d6 f3 58 05 00 0b 00 0a 00 14 00 00 00
0000020 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00
- <STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>
+
<STRONG><A HREF="scr_dump.5.html">scr_dump(5)</A></STRONG>
</PRE>
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