Running jconsole through valgrind picked up a conditional check in jtjprx in f.c depending on an uninitialized value.
The check occurs here: https://github.com/jsoftware/jsource/blob/332c18ced323d33ae50d9551ab4d52d18e158375/jsrc/f.c#L804 The relevant code block being: case 1: // LIT characters. Copy them. If there were boxing characters about, copy one by one and translate if boxing chars // No need to suppress NULs - if the result is LIT, all boxes must have converted to LIT, and would have had NUL converted to space if(nbx){DO(c1, x=*v++; BDC(zv,x);); if(c1<c){v+=c-c1; DDD(zv);}} // Otherwise just move fast Here, nbx can be uninitialized (ie. set to a random memory value) unless certain conditions are met with parsing. It is declared here: https://github.com/jsoftware/jsource/blob/332c18ced323d33ae50d9551ab4d52d18e158375/jsrc/f.c#L706 static A jtjprx(J jt,I ieol,I maxlen,I lb,I la,A w){A y,z;B ch;C e,eov[2],*v,x,*zu,*zv;D lba; I c,c1,h,i,j,k,lc,m,nbx,nq,p,q,r,*s,t,zn; and is initialized in the following line: https://github.com/jsoftware/jsource/blob/332c18ced323d33ae50d9551ab4d52d18e158375/jsrc/f.c#L733 if(ch||AT(w)&BOX+SPARSE)zn+=nbx=countonlines(scanbdc,t,v,h,nq,c,lb,la); It can be demonstrated outside of valgrind by adding a print statement just before the check in line 804 to print the value of nbx. With this print statement in affect, here's a console session: $ ./bin/jconsole 1 nbx: -1692375296 1 <1 nbx: 24 1 $ ./bin/jconsole -lib libj-nonavx.so 1 nbx: 977359104 1 <1 nbx: 24 1 Note that an unboxed expression shows random uninitialized values for nbx on each run. An expression containing the box character triggers the initialization in line 733 and shows a reasonable value. The net affect of this is that the "otherwise move fast" else block in the if loop probably never gets hit unless nbx happens to randomly initialize to zero. -- http://bluishcoder.co.nz ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
