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Diffstat (limited to 'Src/zsh.h')
| -rw-r--r-- | Src/zsh.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/Src/zsh.h b/Src/zsh.h index 28a3c20e9..15b4c404a 100644 --- a/Src/zsh.h +++ b/Src/zsh.h @@ -497,10 +497,28 @@ struct funcdump { char *filename; }; +/* + * A note on the use of reference counts in Eprogs. + * + * When an Eprog is created, nref is set to -1 if the Eprog is on the + * heap; then no attempt is ever made to free it. (This information is + * already present in EF_HEAP; we use the redundancy for debugging + * checks.) + * + * Otherwise, nref is initialised to 1. Calling freeprog() decrements + * nref and frees the Eprog if the count is now zero. When the Eprog + * is in use, we call useeprog() at the start and freeprog() at the + * end to increment and decrement the reference counts. If an attempt + * is made to free the Eprog from within, this will then take place + * when execution is finished, typically in the call to freeeprog() + * in execode(). If the Eprog was on the heap, neither useeprog() + * nor freeeprog() has any effect. + */ struct eprog { int flags; /* EF_* below */ int len; /* total block length */ int npats; /* Patprog cache size */ + int nref; /* number of references: delete when zero */ Patprog *pats; /* the memory block, the patterns */ Wordcode prog; /* memory block ctd, the code */ char *strs; /* memory block ctd, the strings */ |