Hi, Im currently trying to debug a 'error in unprotect: stack imbalance' problem and I am curious about two basic questions on the use of PROTECT and UNPROTECT, which I could not figure out:
- which objects have to be protected, namely, if the code is something like: SEXP fun, e; /* get the expression e ... */ fun = eval(e, R_GlobalEnv); /* or like this?: PROTECT(fun = eval(e, R_GlobalEnv)); */ PROTECT(fun = VECTOR_ELT(fun, 1)); /* do more things with fun ... */ does one need to protect the result of a call to 'eval' immediately? And how about R_tryEval? While searching for code examples in the sources, I found both protected evals and fewer non-protected. - Can someone give a hint (or some documents) on a way to simplify debugging such problem in addition to using gdb, please? I thought about temporarily defining macros such as #define DEBUG_Protect(x) PROTECT(x); fprintf(stderr, "Protecting in %s, l: %d\n", __FILE__, __LINE__) #define UNDEBUG_Protect(x) fprintf(stderr, "Unprotecting %d in %s, l:, %d \n", x , __FILE__, __LINE__); UNPROTECT(x); and then replace all calls temporarily in the package source. But there must be a better way... Thank you very much (and my appologies, if this sounds odd to more experineced c programmers ;) ) Michael ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
