0l, 1l, 2l, 5l, 6l, 8l, kl, ql, tl, vl – loaders|
2l [ option ... ] [ file ... ]|
These commands load the named files into executable files for
the corresponding architectures; see 2c(1) for the correspondence
between an architecture and the character (1, 2, etc.) that specifies
it. The files should be object files or libraries (archives of
object files) for the appropriate architecture. Also, a name like
–lext represents the library libext.a in /$objtype/lib, where objtype
is one of 68000, etc. as listed in 2c(1). The libraries must have
tables of contents (see ar(1)). |
In practice, –l options are rarely necessary as the header files for the libraries cause their archives to be included automatically in the load (see 2c(1)). For example, any program that includes header file libc.h causes the loader to search the C library /$objtype/lib/libc.a. Also, the loader creates an undefined symbol _main (or _mainp if profiling is enabled) to force loading of the startup linkage from the C library.
The order of search to resolve undefined symbols is to load all files and libraries mentioned explicitly on the command line, and then to resolve remaining symbols by searching in topological order libraries mentioned in header files included by files already loaded. When scanning such libraries, the algorithm is to scan each library repeatedly until no new undefined symbols are picked up, then to start on the next library. Thus if library A needs B which needs A again, it may be necessary to mention A explicitly so it will be read a second time.
The loader options are:
The numbers in the above options can begin with 0x or 0 to change the default base from decimal to hexadecimal or octal. The defaults for the values depend on the compiler and the header type.
The loaded image has several symbols inserted by the loader: etext is the address of the end of the text segment; bdata is the address of the beginning of the data segment; edata is the address of the end of the data segment; and end is the address of the end of the bss segment, and of the program.
/$objtype/lib for –llib arguments.|
2c(1), 2a(1), ar(1), nm(1), db(1), prof(1) |
Rob Pike, ``How to Use the Plan 9 C Compiler''
The list of loaders given above is only partial, not all architectures
are supported on all systems, some have been retired and some
are provided by third parties.|