IIRC, you could use longer names than that (in C), but external references only used the first 7 (in C - C symbols had a leading '_' tacked on; I used to know why), 8 (in assembler). Seems unlikely - see below. Someone who actually looked at the source: https://www.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/ld.c instead of just guessing. Give that man a star! I spent a while looking at the code, trying to figure out i) how it works, and ii) what's going wrong with that message, but I don't have a definitive answer. The code is not super well commented, so one has to actually understand what it's doing! :-) It seems to my initial perusal that it maintains two symbol tables, one for globals (which accumulates as each file is processed), and one for locals (which is discarded/reset for each file). As Werner mentioned, the message appears when a local symbol referenced in the relocation information in the current file can't be found (in the local symbol table). It's not, I think, simply due to too many local symbols in an input file - there seems to be a check for that as it's reading the input file symbol table: if (lp >= &local[NSYMPR]) error(1, "Local symbol overflow"); *lp++ = symno; *lp++ = sp; although of course there could be a bug which breaks this check. It seems to me that this is an 'impossible' error, one which can only happen due to i) a bug in the loader (a fencepost error, or something), or ii) an error in the input a.out file. I don't want to spend more time on it, since I'm not sure if you've managed to bypass the problem. If not, let me know, and we'll track it down. (This may involve you addding some printf's so we have more info about the details.) Noel