Do manual do GDB :
definir elementos de impressão número de elementos
Set a limit on how many elements of an array gdb will print. If gdb is printing a large array, it stops printing after it has printed the number of elements set by the set print elements command. This limit also applies to the display of strings. When gdb starts, this limit is set to 200. Setting number-of-elements to zero means that the printing is unlimited.
set print elements 2000
Irá mostrar os primeiros 2000 membros de arrays, cstrings. Como dizem os documentos, definir isso como zero permitirá exibição ilimitada.