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5. Bugs

Bugs reported since the current release as well as older ones may be located via the official distribution site on SourceForge.

Please e-mail bug reports to the gnuplot-bugs mailing list. Or upload the report to the gnuplot web site on SourceForge. Please give complete information on the version of gnuplot you are using and, if possible, a test script that demonstrates the bug. See Seeking-assistance.

The sections below list problems known to be present in gnuplot version 4.2 at the time of release. Some of these are actually bugs in external support libraries and may have been fixed indepently of any changes in gnuplot.


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5.1 Gnuplot limitations

Floating point exceptions (floating point number too large/small, divide by zero, etc.) may occasionally be generated by user defined functions. Some of the demos in particular may cause numbers to exceed the floating point range. Whether the system ignores such exceptions (in which case `gnuplot` labels the corresponding point as undefined) or aborts `gnuplot` depends on the compiler/runtime environment.

The gamma and bessel functions do not work for complex arguments.

If a command line contains a "load" command, then anything on the line after the "load <filename>" is ignored.

Only one color palette at a time is active for any given x11 plot window. This means that multiplots whose constituent plots use different palettes will not display correctly in x11.

Coordinates specified as "time" wrap at 24 hours, and have a precision limited to 1 second. This is in particular a limitation in using time format to handle geographic coordinates.

Error bars are not handled properly in polar/spherical coordinate plot modes.

The 'nohidden3d' option that is supposed to exempt individual plots from the global property 'set hidden3d' does not work for parametric curves.


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5.2 Specific terminals

Some older models of HP plotters do not have a page eject command 'PG'. The current HPGL driver uses this command in HPGL_reset. This may need to be removed for these plotters. The current PCL5 driver uses HPGL/2 for text as well as graphics. This should be modified to use scalable PCL fonts.


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5.3 External libraries

External library GD (used by PNG/JPEG/GIF drivers): Versions of libgd through 2.0.33 contain various bugs in mapping the characters of Adobe's Symbol font. Also it is possible to trigger a library segfault if an anti-aliased line crosses an upper corner of the canvas.

External library PDFlib (used by PDF driver): Gnuplot can be linked against libpdf versions 4, 5, or 6. However, these versions differ in their handling of piped I/O. Therefore gnuplot scripts using piped output to PDF may work only for some versions of PDFlib.

External library svgalib (used by linux and vgagl driver): Requires gnuplot to be suid root (bad!) and has many bugs that are specific to the video card or graphics driver used in X11.

Internationalization (locale settings): Gnuplot uses the C runtime library routine setlocale() to control locale-specific formatting of input and output number, times, and date strings. The locales available, and the level of support for locale features such as "thousands' grouping separator", depend on the internationalization support provided by your individual machine.


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