Dear Gap-Forum,

Richard Rosmanith asked:
> in one of my Gap-Sessions I encountered the following error messages:

gap> for i in [2,4,8,16,32,64,128,256] do
> Print(i,": ",NilpotenzListe(i),"\n\n");
> od;
Error, user interrupt at
while not found and i <= Length( path ) + 1 ... in
ReadPath( LIBNAME, name, ".g", "ReadLib" ) called from
ReadLib( "grpprods" ) called from
main loop
brk> quit;
2: gap>
gap> NilpotenzListe(32);
Syntax error: warning, undefined global variable in /usr/llocal/lib/gap3r4p2/l\
ib/agctbl.g line 74
InfoCharTable2("by GaloisImage");

As you interrupted GAP while it was reading library files, some file was not
read in completely. Thus the functions InfoCharTable1/2 were not defined.
This initiated these error messages while reading in other library files. If
you avoid interrupting you won't get these error messages.
This is no bug but unavoidable standard behaviour.
In this case the error messages seem to be completely harmless (but under
some circumstances interrupting the reading of library files might induce
some very weird errors afterwards). A remedy is never to leave a break loop
by 'quit;' if it had been called from a 'Read' function, but to use 'return;'
If you add the line

InfoRead1:=Print;

to your .gaprc file gap will tell you whenever it is reading a file.

He continues:
> My .gaprc consists of the line:
> and the file "gap/Lag" has the following content:

As the GAP forum is distributed to hundreds of readers I would like to
remind you of the existence of the address 'gap-trouble@math.rwth-aachen.de'
for error reports and questions of rather technical kind. Especially very
long error reports which are supposedly not of interest to other readers
should be sent to this address instead of the forum.

Best regards,

Alexander Hulpke