3.8.1 Loading of a library

Libraries can be loaded with the LIB command:

Syntax:

LIB string_expression ;

Type:

none

Purpose:

reads a library of procedures from a file. If the given filename does not start with . or / and can not be located in the current directory, each directory contained in the library SearchPath is searched for file of this name.

Note on SearchPath:

The the library SearchPath is constructed at SINGULAR start-up time as follows:

1. the directories contained in the environment variable SINGULARPATH are appended
2. the directories $BinDir/LIB, $RootDir/LIB, $RootDir/../LIB, $DefaultDir/LIB, $DefaultDir/../LIB are appended, where
   • $BinDir is the value of the environment variable SINGULAR_BIN_DIR, if set, or, if not set, the directory in which the SINGULAR program resides
   • $RootDir is the value of the environment variable SINGULAR_ROOT_DIR, if set, or, if not set, $BinDir/../.
   • $DefaultDir is the value of the environment variable SINGULAR_DEFAULT_DIR, if set, or /usr/local/Singular/ on a Unix platform, \Singular\ on a Windows 95/98/NT platform, and ::Singular: on a Macintosh.
3. all directories which do not exist are removed from the SearchPath.

For setting environment variables see system, or consult the manual of your shell.

The library SearchPath can be examined by starting up SINGULAR with the option -v, or by issuing the command system("--version");.

Note on standard.lib:

Unless SINGULAR is started with the --no-stdlib option, the library standard.lib is automatically loaded at start-up time.

Only the names of the procedures in the library are loaded, the body of the procedures is read during the first call of this procedure. This minimizes memory consumption by unused procedures. When SINGULAR is started with the -q or --quiet option, no message about the loading of a library is displayed. More precisely, option -q (and likewise --quiet) unsets option loadLib to inhibit monitoring of library loading (see option).

All loaded libraries are displayed by the LIB; command:

  option(loadLib);   // show loading of libraries;
                     // standard.lib is loaded
  LIB;
→ standard.lib
                     // the names of the procedures of inout.lib
  LIB "inout.lib";   // are now known to Singular
→ // ** loaded inout.lib (1.21.2.5,2002/06/12)
  LIB;
→ standard.lib,inout.lib

See Command line options; LIB; Procedures and libraries; SINGULAR libraries; proc; standard_lib; string; system.